Small Noncoding RNAs in Knee Osteoarthritis: The Role of MicroRNAs and tRNA-Derived Fragments

Notopterol mitigates IL-1β-triggered pyroptosis by blocking NLRP3 inflammasome via the JAK2/NF-kB/hsa-miR-4282 route in osteoarthritis

Objective

Osteoarthritis (OA), the most prevalent form of arthritis, impacts approximately 10% of men and 18% of women aged above 60 years. Currently, a complete cure for OA remains elusive, making clinical management challenging. The traditional Chinese herb Notopterygium incisum, integral to the Juanbi pill for rheumatism, shows promise in safeguarding chondrocytes through its strong anti-inflammatory effects.

Methods

To explore the protective effect of notopterol and miRNA (has-miR-4248) against inflammation, we simulated an inflammatory environment in chondrocytes cell lines C20A4 and C28/12, focusing on inflammasome formation and pyroptosis.

Results

Our finding indicates notopterol significantly reduced interleukin (IL)-18 and tumor necrosis factor (TNF)-alpha levels in inflamed cells, curtailed reactive oxygen species (ROS) production post-inflammation, and inhibited the JAK2/STAT3 signaling pathway, thus offering chondrocytes protection from inflammation. Importantly, notopterol also hindered inflammasome assembly and pyroptosis by blocking the NF-κB/NLRP3 pathway through hsa-miR-4282 modulation. In vivo experiments showed that notopterol treatment markedly decreased Osteoarthritis Research Society International (OARSI) scores in OA mice and boosted hsa-miR-4282 expression compared to control groups.

Conclusions

This study underscores notopterol's potential as a therapeutic agent in OA treatment, highlighting its capacity to shield cartilage from inflammation-induced damage, particularly by preventing pyroptosis.

[Xinfeng Capsule alleviates interleukin-1β-induced chondrocyte inflammation and extracellular matrix degradation by regulating the miR-502-5p/TRAF2/NF-κB axis]

OBJECTIVE

To investigate the mechanism that mediates the inhibitory effect of Xinfeng Capsule (XFC) on interleukin (IL)-1β-induced impairment of chondrocytes.

METHODS

XFC-medicated serum was collected from SD rats with XFC gavage, and its optimal concentration for chondrocyte treatment was determined using Cell Counting Kit-8 assay and flow cytometry. Dual luciferase reporter analysis was performed to analyze the targeting relationship between miR-502-5p and TRAF2. In cultured human chondrocytes induced with IL-1β, the effects of transfection with miR-502-5p inhibitor and XFC-medicated serum, alone or in combination, on expression levels of IL-1β, tumor necrosis factor-α (TNF-α), IL-4, and IL-10 were examined with ELISA, and the changes in the expressions of collagen type Ⅱ alpha 1 (COL2A1), matrix metalloproteinase 13 (MMP13), adisintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5), and miR-502-5p/TRAF2/NF-κB axis gene expression were detected using RT-qPCR, Western blotting, and immunofluorescence assay.

RESULTS

In cultured human chondrocytes, treatment with IL-1β significantly decreased the cell viability, increased cell apoptosis rate, lowered miR-502-5p, IL-4, IL-10, and COL2A1 expressions, and enhanced IL-1β, TNF-α, ADAMTS5, MMP13, TRAF2, and NF-κB p65 expressions (P < 0.05), and these changes were significantly improved by treatment with XFC-medicated serum at the optimal concentration of 20% (P < 0.05). Transfection of the chondrocytes with miR-502-5p inhibitor resulted in elevated expressions of IL-1β, TNF-α, ADAMTS5, MMP13, TRAF2, and NF-κB p65 and lowered expressions of miR-502-5p, IL-4, IL-10, and COL2A1, and XFC-medicated serum obviously reversed the effects of miR-502-5p inhibitor.

CONCLUSION

XFC can inhibit IL-1β-induced inflammatory response and ECM degradation in cultured human chondrocytes possibly by regulating the miR-502-5p/TRAF2/NF-κB axis.

Bauhinia championii alleviates extracellular matrix degradation in IL-1β induced chondrocytes via miRNA-145-5p/TLR4/NF-κB axis

Bauhinia championii is a herbal medicine used to treat osteoarthritis (OA) in Chinese traditional medicine. However, the molecular mechanisms underlying the therapeutic effects of this medicinal herb against OA have rarely been reported. Given that it has been established that extracellular matrix metabolism plays an important role in the pathogenesis of OA, the present study focused on the effects and mechanisms of Bauhinia championii in the regulation of extracellular matrix metabolism in chondrocytes induced by IL-1β. Rat chondrocytes were isolated, cultured and identified in vitro. The CCK-8 method was used to detect the cell viability of Bauhinia championii aqueous extract (BCAE)-treated chondrocytes. The chondrocyte inflammatory and degeneration models were induced by 10 ng/mL IL-1β, then chondrocytes were grouped into different groups to evaluate the effect of BCAE on extracellular matrix degradation and the regulation of TLR4/NF-κB signaling pathway. Furthermore, whether the regulatory effect of BCAE on TLR4/NF-κB signaling pathway is related to miRNA-145-5p was also investigated by cell transfection. We found that BCAE promoted chondrocyte viability in a dose- and time-dependent manner. BCAE delayed chondrocyte degeneration induced by IL-1β. BCAE could reduce the degradation of the cartilage extracellular matrix by inhibiting the TLR4/NF-κB signaling pathway. miRNA-145-5p negatively regulated the expression of TLR4 in chondrocytes, while BCAE could upregulate the expression of miRNA-145-5p in chondrocytes induced by IL-1β. These results suggest that BCAE upregulates the expression of miRNA-145-5p to inhibit the TLR4/NF-κB signaling pathway, thereby alleviating the metabolic imbalance of the extracellular matrix and protecting chondrocytes from degeneration.

Bibliometric Analysis of Publications in Clinical Trials on Knee Osteoarthritis Between 2001 and 2022

Purpose

Clinical treatment of knee osteoarthritis has gained great interest, and numerous clinical studies have been reported. Few studies have described the detailed characterizations of clinical trials on knee osteoarthritis. This study is to identify, visualize, and characterize the clinical trials in knee osteoarthritis research.

Design and Methods

Articles published in recent two decades were extracted from the Web of Science core collection database using a query based on MeSH terms and topics of knee osteoarthritis and clinical trial. Basic characteristics of publications were analyzed based on the publication year, authors, institutions, counties, and keywords covered in the article. CiteSpace and VOS viewer were used for data visualization. The data were retrieved on May 28, 2022.

Results

A total of 1972 trials on knee osteoarthritis were identified. The number of publications has experienced rapid growth in the past two decades. America, England, and China had strong contributions in publication. Osteoarthritis and Cartilage, Annals of the Rheumatic Diseases and American Journal of Sports Medicine were highly cited and bellwether journals. Clustering mapping of the collaborative network, co-citation, and co-occurrence analyses showed that the research hotspots are mainly focused on disease-modifying medications, intra-articular injections, physical therapy for symptom control, lifestyle intervention, Chinese medicine treatment, and knee replacement.

Conclusion

Clinical treatments of knee OA are evolving. Pharmacologic therapy, intra-articular therapy, nonpharmacologic therapy including exercise or diet, self-management programs, Chinese medicine treatment, and knee replacement were highly represented in clinical trials of knee OA. Adjustment of combination therapy may be the next study focus in the future.

The emerging roles of tRNAs and tRNA-derived fragments during aging: Lessons from studies on model organisms

Aging is a gradual decline of various functions of organisms resulting in diminished abilities to protect against the environmental damage and reinforce the physiological harmony. Age-related functional declines have been thought to be passive and not regulated. However, studies on numerous model organisms, from yeast to mammals, exposed that the mechanisms of lifespan regulation are remarkably conserved throughout the evolution. Following the pioneering genetic studies in C. elegans, it has been shown that the genes related to the longevity are conserved in yeast, flies and mice. For a long time, tRNAs have been only considered as molecules transporting amino acids to the ribosome during translation. Nonetheless, it has become apparent from many biological studies that tRNAs are entangled in a variety of physiological and pathological processes. This review focuses on the emerging roles of tRNA-associated processes in aging and lifespan of model organisms. More specificaly, we present a summary on the importance of tRNA metabolism, epitranscriptome and possible roles of tRNA-derived fragments in aging and lifespan regulation. Better understanding of the basic mechanisms of aging could lead to the development of new diagnostics and treatments for aging-related diseases.

Negative effects of heat stress on ovarian tissue in female rabbit

Numerous studies have highlighted the role of miRNA in the deformation and necrosis of cells of ovarian tissue caused by heat stress (HS), which ultimately affects ovarian function. Although the role of small RNAs has been investigated in alterations in ovarian tissue functioning in response to HS, the expression profile of ovarian miRNA has been explored to a lesser extent. In this study, female rabbits were subject to HS treatment by using electrical heater. The current work demonstrated that HS could significantly change physiological performance of female rabbits including body weight, rectal temperature and relative ovary weight, and significantly reduce serum IL-2, IL-8, CAT, and GSH-Px concentrations by enzyme-linked immunosorbent assay (ELISA) technique. As a result, an increase in apoptosis in ovarian cells, as well as unhealthy follicles, were observed by Hematoxylin-eosin (HE) and TUNEL staining. Additionally, small RNA-seq revealed changes in the miRNA expression profile of rabbit ovaries under HS. Five hundred fourteen miRNAs were obtained including known miRNAs 442 and novel miRNAs 72. Among these miRNAs, 23 miRNAs were significantly expressed under HS. Eleven differentially expressed miRNAs (DE miRNAs) and 9 their predicted targets were confirmed by qPCR, which were expected miRNA-mRNA negative regulation pattern. Among the DE miRNAs and targets, miR-141-39 may target COQ6, miR-449a-5p and miR-34c-5p may control RFC5 and RTN2 together, miR-449a-5p may target ACADVL, miR-34c-5p potentially targets Bcl-2 and miR-196b-5p potentially regulates CASK and HOXB6. Thus, the current work suggested the negative effects of HS on the ovarian tissue of female rabbits, and in conclusion these changes could be caused by decreased serum IL-2, IL-8, CAT and GSH-Px levels, increased ovarian apoptosis, and changed the expression of miRNAs.

miR-219a-5p inhibits the pyroptosis in knee osteoarthritis by inactivating the NLRP3 signaling via targeting FBXO3

PURPOSE

This work was to identify the function and mechanism of miR-219a-5p in regulating knee osteoarthritis (KOA).

METHODS

Rat fibroblast-like synoviocytes (FLSs) were isolated to construct KOA cell model by lipopolysaccharide and adenosine triphosphate treatment. miR-219a-5p and FBXO3 expression in FLSs was modulated by transfection. Flow cytometry was executed to research FLSs apoptosis. Caspase-1 and IL-1β expression in FLSs was researched by immunofluorescence. The binding between miR-219a-5p and FBXO3 was identified by dual luciferase reporter gene assay. KOA rat model and miR-219a-5p up-modulation KOA rat model were constructed. Step size of rats was analyzed. Knee joints of rats were experienced Safranin O-fast green staining to evaluate the knee joint injury. FBXO3, pyroptosis-associated proteins, and IL-1β and IL-18 expression in FLSs and articular cartilage tissues of rats were assessed by Western blot, qRT-PCR and Enzyme-linked immunosorbent assay.

RESULTS

KOA cell model had higher apoptosis percentage, expression of pyroptosis-associated proteins, and IL-1β and IL-18 level. miR-219a-5p up-modulation decreased the above indicators, whereas miR-219a-5p down-modulation increased the above indicators. FBXO3 expression was directly repressed by miR-219a-5p. Loss of FBXO3 suppressed the above indicators. FBXO3 counteracted the suppression of miR-219a-5p on the above indicators. miR-219a-5p agomir attenuated knee joint injury, increased step size of KOA rats, and reduced FBXO3, pyroptosis-associated proteins and level of IL-1β and IL-18 in the articular cartilage tissues of KOA rats.

CONCLUSION

miR-219a-5p suppressed the pyroptosis in KOA by inactivating the NLRP3 signaling via targeting FBXO3, which might be a promising target for ameliorating KOA in the clinic.

Traditional Chinese medicine ointment combined with tuina therapy in treatment of pain and swelling after total knee arthroplasty

BACKGROUND

The most effective treatment for knee joint pain is total knee arthroplasty (TKA), but the risk of pain and swelling in patients after surgery is high. Ice application, ankle pump exercise and non-steroidal anti-inflammatory painkillers are the primary clinical treatments after surgery. However, long-term use of non-steroidal anti-inflammatory pain relievers can easily cause gastrointestinal damage. Traditional Chinese medicine (TCM) ointments and tuina therapy integrate TCM and manipulation, which effectively promotes the penetration of TCM into the skin lesions, improves local blood circulation and inflammatory reaction and has good long-term effects on patients.

AIM

To evaluate the efficacy of TCM ointment combined with tuina therapy in the treatment of pain and swelling after TKA.

METHODS

The randomized controlled clinical trial enrolled 80 patients who underwent TKA via the same procedure. The patients were randomly divided among the treatment group (n = 40) and the control group (n = 40). The control group was given an analgesia pump in addition to oral painkillers as the postoperative intervention. The treatment group received TCM ointment with tuina therapy in addition to the analgesia pump and oral painkillers in the postoperative period. The following variables were recorded 3 d before surgery and 3 d, 7 d and 14 d after surgery: Visual analogue scale (VAS) score; skin temperature; circumferences at 15 cm above and below the patella; maximum active knee flexion angle; and the knee injury and Osteoarthritis Outcome score (KOOS).

RESULTS

After treatment, VAS was significantly lower in the treatment group than the control group at 7 d (t = 7.536, P < 0.001) and 14 d (t = 8.563, P < 0.001). The skin temperature of participants in the treatment group was significantly lower than that in the control group at 7 d (t = 2.968, P = 0.004) and 14 d (t = 4.423, P < 0.001). The circumference values of the two positions in the treatment group were lower than those in the control group at 7 d [t = 2.315, P = 0.023 (above); t = 2.121, P = 0.037 (below)] and 14 d [t = 2.374, P = 0.020 (above); t = 2.095, P = 0.039 (below)]. After 14 d of treatment, the maximum active knee flexion angle and KOOS of the two groups were significantly improved but were significantly higher in the treatment group (P < 0.05 for both).

CONCLUSION

TCM ointment and tuina therapy have significant advantages over standard care in the treatment of pain and swelling after TKA. This additional treatment may improve knee function but additional studies are needed to confirm our observations.

Harnessing hyaluronic acid for the treatment of osteoarthritis: A bibliometric analysis

Background: Osteoarthritis (OA) is a common disease which usually occurs in middle-aged and elderly people. Hyaluronic acid (HA) has been widely used to treat OA and related researches on the efficacy and safety of HA in the treatment of OA have been published. Therefore, the purpose of this research was to investigate the subject characteristics of harnessing HA for the treatment of OA and to analyse the relevant trends and hotspots by using a bibliometric approach.

Methods: The articles published from 1 January 2002 to 31 December 2021 were searched in the Web of Science Core Collection (WoSCC) and the relevant information of HA for the treatment of OA was extracted after screening. Then, a total of 2438 publications were analysed by using Microsoft Excel, CiteSpace 5.8.R3, VOSviewer 1.6.18 and the Online Analysis Platform of Literature Metrology (http://bibliometric.com/).

Results: A total of 2438 articles were finally included for analysis. The number of publications increased year by year. A total of 83 coutries and 3319 institutions published 2438 manuscripts in the field of use HA for the treatment of OA. The most productive country was United States with total 689 publications and League of European Research Universities Leru (Belgium) was the leading institution with total 126 publicatios. In terms of authors, the most prominent author was KrausVB, who published 28 papers with the highest H-index (19). In addition, Osteoarthritis and Cartilage had the highest number of publications (152 articles) and the highest number of citations (6450 citations). The co-cited references analysis indicated that the article published by McAlindon in 2014 had the most highest number of citations (91co-citations). What’s more, most research hotspots focused on the efficacy and safety of HA, and regenerative medicine researches such as platelet-rich plasma (PRP) and mesenchymal stem cells (MSCs) have attracted more and more attentions of researchers.

Conclusion: This study visually analyzed the historical evolution and future trends of HA for the treatment of OA, and discussed the research priorities. At present, there are still different views on the efficacy of HA for the treatment of OA. Gradually, research hotspots of this field have focused on the regenerative medicine.

Transfer RNAs-derived small RNAs and their application potential in multiple diseases

The role of tRNAs is best known as adapter components of translational machinery. According to the central dogma of molecular biology, DNA is transcribed to RNA and in turn is translated into proteins, in which tRNA outstands by its role of the cellular courier. Recent studies have led to the revision of the canonical function of transfer RNAs (tRNAs), which indicates that tRNAs also serve as a source for short non-coding RNAs called tRNA-derived small RNAs (tsRNAs). tsRNAs play key roles in cellular processes by modulating complicated regulatory networks beyond translation and are widely involved in multiple diseases. Herein, the biogenesis and classification of tsRNAs were firstly clarified. tsRNAs are generated from pre-tRNAs or mature tRNAs and are classified into tRNA-derived fragments (tRFs) and tRNA halves (tiRNA). The tRFs include five types according to the incision loci: tRF-1, tRF-2, tRF-3, tRF-5 and i-tRF which contain 3′ tiRNA and 5′ tiRNA. The functions of tsRNAs and their regulation mechanisms involved in disease processes are systematically summarized as well. The mechanisms can elaborate on the specific regulation of tsRNAs. In conclusion, the current research suggests that tsRNAs are promising targets for modulating pathological processes, such as breast cancer, ischemic stroke, respiratory syncytial virus, osteoporosis and so on, and maintain vital clinical implications in diagnosis and therapeutics of various diseases.

Changes in Small Noncoding RNA Expression during Chondrocyte Senescence

OBJECTIVE

Osteoarthritis (OA) is characterized by the chronic and progressive deterioration of articular cartilage. Chondrocyte senescence could lead to a shift in the balance between extracellular matrix (ECM) component synthesis and degradation. Small noncoding RNAs (sncRNAs), including microRNAs (miRNAs), P-element-induced wimpy testis-(PIWI-) interacting RNAs (piRNAs), small nucleolar RNAs (snoRNAs), small nuclear RNAs (snRNAs), and repeat-associated siRNAs (rasiRNAs), are a class of important epigenetic molecules. We aimed to gain insights into the changes and roles of sncRNA in chondrocyte senescence.

DESIGN

Healthy mouse postnatal chondrocytes were isolated, and a replicative aging model was constructed. We used small RNA sequencing (small RNA-seq) to generate extensive small RNA data. We identified differentially expressed sncRNAs and performed tissue-specific analysis using real-time quantitative polymerase chain reaction (qRT-PCR). β-galactosidase staining was used to detect chondrocyte senescence. The results showed that the expression profiles of sncRNA in passage 5 chondrocytes were significantly different from those in passage 0 chondrocytes. The expression of sncRNA was tissue specific. We found that 40 miRNAs were upregulated and 70 miRNAs were downregulated during chondrocyte senescence, and that miR-132-5p expression inhibition prevented chondrocyte senescence. We found that 8 piRNAs were upregulated and 17 piRNAs were downregulated during chondrocyte senescence, and that piRNA piR_025576 overexpression delayed chondrocyte senescence. We found that 24 snoRNAs were upregulated and 28 snoRNAs were downregulated during chondrocyte senescence, and that snoRNA ENSMUSG00000087935 overexpression delayed chondrocyte senescence. We found that 5 snRNAs were upregulated and 6 snRNAs were downregulated during chondrocyte senescence, and that snRNA ENSMUSG00000064682 overexpression delayed chondrocyte senescence. We found that 1 rasiRNA was upregulated and 4 rasiRNAs were downregulated during chondrocyte senescence.

CONCLUSIONS

These findings might provide novel insights into OA pathogenesis and contribute to the development of candidates for targeted therapeutics in OA.

Cartilage Homeostasis and Osteoarthritis

Healthy limb joints are important for maintaining health and attaining longevity. Endochondral ossification (the replacement of cartilage with bone, occurring during skeletal development) is essential for bone formation, especially in long-axis bones. In contrast to endochondral ossification, chondrocyte populations in articular cartilage persist and maintain joint tissue into adulthood. Articular cartilage, a connective tissue consisting of chondrocytes and their surrounding extracellular matrices, plays an essential role in the mechanical cushioning of joints in postnatal locomotion. Osteoarthritis (OA) pathology relates to disruptions in the balance between anabolic and catabolic signals, that is, the loss of chondrocyte homeostasis due to aging or overuse of cartilages. The onset of OA increases with age, shortening a person’s healthy life expectancy. Although many people with OA experience pain, the mainstay of treatment is symptomatic therapy, and no fundamental treatment has yet been established. To establish regenerative or preventative therapies for cartilage diseases, further understanding of the mechanisms of cartilage development, morphosis, and homeostasis is required. In this review, we describe the general development of cartilage and OA pathology, followed by a discussion on anabolic and catabolic signals in cartilage homeostasis, mainly microRNAs.

Epigenetic modifications in spinal ligament aging

Spinal stenosis is a common degenerative spine disorder in the aged population and the spinal ligament aging is a main contributor to this chronic disease. However, the underlying mechanisms of spinal ligament aging remain unclear. Epigenetics is the study of heritable and reversible changes in the function of a gene or genome that occur without any alteration in the primary DNA sequence. Epigenetic alterations have been demonstrated to play crucial roles in age-related diseases and conditions, and they are recently studied as biomarkers and therapeutic targets in the field of cancer research. The main epigenetic modifications, including DNA methylation alteration, histone modifications as well as dysregulated noncoding RNA modulation, have all been implicated in spinal ligament aging diseases. DNA methylation modulates the expression of critical genes including WNT5A, GDNF, ACSM5, miR-497 and miR-195 during spinal ligament degeneration. Histone modifications widely affect gene expression and obvious histone modification abnormalities have been found in spinal ligament aging. MicroRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) exert crucial regulating effects on spinal ligament aging conditions via targeting various osteogenic or fibrogenic differentiation related genes. To our knowledge, there is no systematic review yet to summarize the involvement of epigenetic mechanisms of spinal ligament aging in degenerative spinal diseases. In this study, we systematically discussed the different epigenetic modifications and their potential functions in spinal ligament aging process.

Genetic biomarkers in osteoarthritis: a quick overview

Osteoarthritis (OA) is a chronic musculoskeletal disease with a polygenic and heterogeneous nature. In addition, when clinical manifestations appear, the evolution of the disease is usually already irreversible. Therefore, the efforts on OA research are focused mainly on the discovery of therapeutic targets and reliable biomarkers that permit the early identification of different OA-related parameters such as diagnosis, prognosis, or phenotype identification. To date, potential candidate protein biomarkers have been associated with different aspects of the disease; however, there is currently no gold standard. In this sense, genomic data could act as complementary biomarkers of diagnosis and prognosis or even help to identify therapeutic targets of the disease. In this review, we will describe the most recent advances in genetic biomarkers in OA over the past three years.