Triptolide promotes the apoptosis and attenuates the inflammation of fibroblast-like synoviocytes in rheumatoid arthritis by down-regulating lncRNA ENST00000619282

A synergistic effect of triptolide and curcumin on rheumatoid arthritis by improving cell proliferation and inducing cell apoptosis via inhibition of the IL-17/NF-κB signaling pathway

Rheumatoid arthritis (RA) is a chronic, progressive, systemic autoimmune disease. While triptolide (TPL) and curcumin (CUR) are known to have multiple beneficial effects on RA, the combined effect of TPL and CUR remains unexplored. This study aimed to investigate their synergistic effect on cell proliferation and apoptosis via the IL-17/NF-κB signaling pathway. The collagen-induced arthritis (CIA) rat model was established, showing severe joint and synovial damage compared to normal rats. Treatment with TPL and CUR reduced the severity of RA in the CIA rat model and alleviated serum inflammatory cytokines, such as rheumatoid factor, IL-17, TNF-α, IL-1β, and IL-6. The elevated levels of IL-17 and NF-κB in CIA rats were also inhibited, and the resistant apoptosis was aggravated by TPL and CUR. In vitro, the improvement of cell proliferation and induction of apoptosis were observed in LPS-stimulated MH7A cells treated with TPL and CUR, associated with the inhibition of the IL-17/NF-κB signaling pathway. Taken together, a synergistic effect of TPL and CUR on RA may involve relieving symptoms, improving excessive proliferation, inducing apoptosis resistance, and inhibiting the IL-17/NF-κB signaling pathway.

Integrated single-cell and bulk RNA sequencing identifies POSTN as a potential biomarker and therapeutic target for rheumatoid arthritis

BACKGROUND

This study aimed to integrate single-cell RNA sequencing (scRNA-seq) and bulk RNA-seq data to identify potential biomarkers and therapeutic targets for rheumatoid arthritis (RA).

METHOD

Firstly, we obtained the synovial scRNA-seq data from the Immport database and bulk RNA-seq data from the Gene Expression Omnibus (GEO) database. Then, we used weighted gene correlation network analysis (WGCNA) to screen for module genes most relevant to RA and intersected them with the differentially expressed genes (DEGs) obtained from scRNA-seq and bulk RNA-seq to obtain intersecting genes. Next, we constructed a protein-protein interaction (PPI) network of hub genes using the STRING database and Cytoscape software and validated its expression using external validation cohorts. Finally, we performed immune cell infiltration analysis using CIBERSORT and explored the expression and drug binding activity of key gene using clinical samples and molecular docking, respectively.

RESULT

We identified six cellular subgroups through dimensionality reduction and clustering, and fibroblasts may be the most important cell cluster in RA based on pseudotime and cell-cell communication analyses. Subsequently, we intersected module genes with DEGs obtained from scRNA-seq and bulk RNA-seq and constructed a PPI network of hub genes (BGN, COL11A1, COL1A1, GUCY1A1, POSTN). In external validation cohorts, POSTN was highly expressed and demonstrated the highest diagnostic performance (AUC = 0.716). In subsequent analyses, we defined POSTN as a key gene and found that its expression level was positively correlated with M2 macrophages in immune cell infiltration analysis. Additionally, POSTN was upregulated in clinical samples and exhibited favorable binding activity with nine anti-rheumatoid arthritis drugs (affinity ≤ -6.0 kcal/mol).

CONCLUSION

Through bioinformatics analysis, clinical sample validation, and molecular docking, we found that POSTN was highly expressed in RA and stably bound to common anti-rheumatoid arthritis drugs, which will provide new insights into potential biomarkers and therapeutic targets for RA.

LncRNA SLC9A3-AS1 knockdown increases the sensitivity of liver cancer cell to triptolide by regulating miR-449b-5p-mediated glycolysis

Triptolide (TP) is involved in the progression of liver cancer. However, the detailed molecular network regulated through TP is still unclear. Long non-coding RNA (LncRNA) SLC9A3 exerts roles in various pathological progresses. Nevertheless, whether SLC9A3 affects the sensitivity of liver cancer cells to TP have not been uncovered. The content of SLC9A3-AS1 and miR-449b-5p was estimated by utilizing quantitative real-time polymerase-chain reaction (qRT-PCR). Cell counting kit 8 (CCK-8) assay was introduced to assess cell viability. Additionally, cell viability as well as invasion was tested via transwell assay. The direct binding between miR-449b-5p and SLC9A3-AS1 or LDHA was confirmed through luciferase reporter gene assay. Moreover, glycolysis rate was tested by calculating the uptake of glucose in addition to the production of lactate in Huh7 cells. LncRNA SLC9A3-AS1 was up-regulated in liver cancer tissue samples and cells. Knockdown of SLC9A3-AS1 notably further inhibited viability, migration as well as invasion in Huh7 cells. MiR-449b-5p was the direct downstream miRNA of SLC9A3-AS1 and was down-regulated by SLC9A3-AS1 in Huh7 cells. In addition, miR-449b-5p was reduced in liver cancer tissues and cells. Overexpressed miR-449b-5p increased the sensitivity of Huh7 cells to TP remarkably. Moreover, miR-449b-5p negatively regulated LDHA expression in Huh7 cells. This work proved that SLC9A3-AS1 increased the sensitivity of liver cancer cells to TP by regulating glycolysis rate mediated via miR-449b-5p/LDHA axis. These findings implied that TP is likely to be a potent agent for treating patients diagnosed with liver cancer.

Regulating the lncRNA DSCR9/RPLP2/PI3K/AKT axis: an important mechanism of Xinfeng capsules in improving rheumatoid arthritis

Background

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic and symmetrical polyarthritis. RA patients often experience inflammatory reaction and hypercoagulable state, which together affect the self-perception of patient (SPP). Currently, inhibiting inflammation and hypercoagulable state are common treatment methods for alleviating RA symptoms. Xinfeng Capsules (XFC) has a long history of treating RA, and can effectively improve the inflammatory response and hypercoagulable state of RA. However, the potential mechanisms have not yet been determined.

Purpose and study design

This study elucidated the action mechanism of XFC in RA inflammation and hypercoagulability through the lncDSCR9/RPLP2/PI3K/AKT axis.

Results

Clinical observations indicated that there was a strong link between XFC therapy and improvements in inflammatory and coagulation biomarkers, as well as SPP among RA patients. The subsequent network pharmacology analysis results identified the PI3K/AKT signaling pathway as a potential mediator for XFC treatment of RA. Furthermore, clinical validation and sequencing results revealed that lncRNA DSCR9 expression (a gene implicated in inflammation and coagulation) was negatively correlated with clinical markers of inflammation and coagulation, while positively correlated with SF-36 indicators. Notably, XFC treatment remarkably upregulated lncRNA DSCR9 expression and downregulated PI3K and AKT expressions, showing opposite expression trends to the untreated cases.The regulatory effect of XFC on the lncRNA DSCR9/RPLP2/PI3K/AKT axis in RA was investigated using techniques such as RNA pull-down assay, Western blot analysis, RT-PCR, and EdU assay. Moreover, the administration of the PI3K/AKT agonist RMH can counteract the effects of XFC on p-PI3K, p-AKT, inflammation, and hypercoagulability, reinforcing the role of pathway. Finally, animal studies utilizing HE staining and transmission electron microscopy (TEM) demonstrated that XFC notably decreased PI3K and AKT expressions in adjuvant-induced arthritis (AA) rats, mitigated inflammation and hypercoagulability, and enhanced the ultrastructure of synovial cells. These findings underscored the potential mechanisms of XFC in the treatment of RA.

Conclusion

Regulating the lncRNA DSCR9/RPLP2/PI3K/AKT axis may be an important mechanism by which XFC improved RA inflammatory response and hypercoagulable state.

Exposome: Epigenetics and autoimmune diseases

Systemic autoimmune diseases are complex conditions characterized by an immune system dysregulation and an aberrant activation against self-antigens, leading to tissue and organ damage. Even though genetic predisposition plays a role, it cannot fully explain the onset of these diseases, highlighting the significant impact of non-heritable influences such as environment, hormones and infections. The exposome represents all those factors, ranging from chemical pollutants and dietary components to psychological stressors and infectious agents. Epigenetics, which studies changes in gene expression without altering the DNA sequence, is a crucial link between exposome and the development of autoimmune diseases. Key epigenetic mechanisms include DNA methylation, histone modifications, and non-coding RNAs. These epigenetic modifications could provide a potential piece of the puzzle in understanding systemic autoimmune diseases and their connection with the exposome. In this work we have collected the most important and recent evidence in epigenetic changes linked to systemic autoimmune diseases (systemic lupus erythematosus, idiopathic inflammatory myopathies, ANCA-associated vasculitis, and rheumatoid arthritis), emphasizing the roles these changes may play in disease pathogenesis, their potential as diagnostic biomarkers and their prospective in the development of targeted therapies.

Quantitative proteomic analysis of circulating exosomes reveals the mechanism by which Triptolide protects against collagen-induced arthritis

INTRODUCTION

Triptolide (TP), a natural product derived from the herbal medicine Tripterygium wilfordii, exhibits potent immunosuppressive activity. However, the mechanisms underlying its effects in rheumatoid arthritis remain incompletely understood.

METHODS

Collagen-induced arthritis (CIA) model was induced in Sprague-Dawley rats by immunization with bovine type II collagen, and TP was administrated as treatment. The therapeutic effect of TP was evaluated based on paw swelling, histopathology, and serum levels of inflammatory factors. Exosomes isolated from rat serum were characterized by transmission electron microscopy, dynamic light scattering, and western blot analysis. Proteomic profiling of exosomes was analyzed by direct DIA quantitative proteomics analysis. Gene ontology and the Kyoto Encyclopedia of Genes and Genomes databases were employed for enrichment analysis related to molecular function, biological processes, and signaling pathways. Western blot analysis was used to analyze differentially expressed proteins.

RESULTS

TP treatment ameliorated arthritic phenotypes in CIA rats as evidenced by reduced arthritis score, paw swelling, pathological injury severity scores, and serum levels of inflammatory cytokines. The proteomic analysis revealed that TP treatment significantly inhibited complement and coagulation cascades, interleukin-17 signaling pathway, and cholesterol metabolism, which were reactivated in CIA rats. Importantly, lipocalin 2 (LCN2) and myeloperoxidase (MPO) levels were markedly upregulated in the CIA group but suppressed upon TP administration. Furthermore, in synovial tissues, LCN2 and MPO expression levels were also elevated in the CIA group but decreased following TP treatment.

CONCLUSION

Our findings demonstrate that TP alleviates CIA, possibly through modulation of exosomal LCN2 and MPO proteins.

Antitumor mechanisms and future clinical applications of the natural product triptolide

Triptolide (TPL) is a compound sourced from Tripterygium wilfordii Hook. F., a traditional Chinese medicinal herb recognized for its impressive anti-inflammatory, anti-angiogenic, immunosuppressive, and antitumor qualities. Notwithstanding its favorable attributes, the precise mechanism through which TPL influences tumor cells remains enigmatic. Its toxicity and limited water solubility significantly impede the clinical application of TPL. We offer a comprehensive overview of recent research endeavors aimed at unraveling the antitumor mechanism of TPL in this review. Additionally, we briefly discuss current strategies to effectively manage the challenges associated with TPL in future clinical applications. By compiling this information, we aim to enhance the understanding of the underlying mechanisms involved in TPL and identify potential avenues for further advancement in antitumor therapy.

LncRNA expression profiling in exosomes derived from synovial fluid of patients with rheumatoid arthritis

OBJECTIVE

To identify the long non-coding RNA (lncRNA) expression profiling in exosomes derived from synovial fluid of rheumatoid arthritis (RA) patients, and carry out bioinformatics analysis on target genes of differentially expressed lncRNAs.

METHODS

Exosomes were isolated from synovial fluid via ultracentrifugation. RNAs were extracted from exosomes by using HiPure Liquid RNA/miRNA kits, followed by lncRNA sequencing. Differentially expressed lncRNAs in RA were screened, and bioinformatics analysis of their target genes was carried out. qRT-PCR was used to verify the lncRNA expression levels.

RESULTS

Compared with osteoarthritis (OA), 347 lncRNAs were found differentially expressed in RA. Compared with gout, 805 lncRNAs were found differentially expressed in RA. Compared with both OA and gout, 85 lncRNAs were found specially expressed in RA (65 were upregulated (including ENST00000433825.1)). Functional analysis of target genes of the specially expressed lncRNAs revealed significant enrichment of "autophagy" and "mTOR signaling pathway". The qRT-PCR results indicated that ENST00000433825.1 was highly expressed in RA, compared with both OA and gout (P < 0.05), which matched the lncRNA sequencing results. Correlation analysis showed that the level of ENST00000433825.1 in RA patients was significantly and positively correlated with the level of C-reactive protein (CRP) (P < 0.001).

CONCLUSIONS

The lncRNA expression profiling in exosomes derived from synovial fluid of RA was significantly different from OA and gout. ENST00000433825.1 was highly and uniquely expressed in RA and significantly and positively correlated with CRP, which might provide a diagnostic and therapeutic biomarker for RA.

Non-coding RNAs involved in fibroblast-like synoviocyte functioning in arthritis rheumatoid: From pathogenesis to therapy

Rheumatoid arthritis (RA) is a polygenic autoimmune disorder with an uncertain etiology, primarily impacting the joints. Moreover, the disease may manifest beyond articular involvement, leading to extra-articular manifestations. Fibroblast-like synoviocytes (FLS) are cells of mesenchymal origin that possess crucial physiological significance within the synovium, contributing to the synthesis of specific constituents found in the synovial fluid and articular cartilage. Consequently, there has been a growing focus on FLS as a potential therapeutic target in the context of RA. Recent investigations have revealed that non-coding RNAs (ncRNAs) serve as pivotal regulators of FLS function, with their dysregulated expression patterns being detected within FLS populations. NcRNAs, such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), assume essential functions as regulators of gene expression at both the post-transcriptional and transcriptional levels, and also serve as guiding molecules for chromatin-modifying complexes. Majority of these ncRNAs contribute to various FLS activities including metastasis, proliferation, and cytokine production. In the current work, we comprehensively review the existing literature on ncRNAs, which play pivotal roles in FLS activity and the pathogenesis of RA. Furthermore, this study provides a comprehensive summary and description of the lncRNA/circRNA-miRNA-mRNA regulatory axes in FLS activity, along with potential implications for the RA development. As well, in the final section, we illustrated that therapeutic agents including herbal medicine, and exosomes by modulating ncRNAs regulate FLS activity.

Long noncoding RNA/circular RNA regulates competitive endogenous RNA networks in rheumatoid arthritis: molecular mechanisms and traditional Chinese medicine therapeutic significances

Rheumatoid arthritis (RA) is a systemic and autoimmune disease that is mainly featured abnormal fibroblast-like synoviocyte (FLS) proliferation and inflammatory cell infiltration. Abnormal expression or function of long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) are closely related to human diseases, including RA. There has been increasing evidence showing that in the competitive endogenous RNA (ceRNA) networks, both lncRNA and circRNA are vital in the biological functions of cells. Nevertheless, the exact mechanism of ceRNA in RA remains to be investigated. Herein, we summarized the molecular potencies of lncRNA/circRNA-mediated ceRNA networks in RA, with emphasis on the phenotypic regulation of ceRNA in the progression of RA, including regulation of proliferation, invasion, inflammation and apoptosis, as well as the role of ceRNA in traditional Chinese medicine (TCM) in the treatment of RA. In addition, we also discussed the future direction and potential clinical value of ceRNA in the treatment of RA, which may provide potential reference value for clinical trials of TCM therapy for the treatment of RA.Key messagesLong noncoding RNA/circular RNA can work as the competitive endogenous RNA sponge and participate in the pathogenesis of rheumatoid arthritis.Traditional Chinese medicine and its agents have shown potential roles in the prevention and treatment of rheumatoid arthritis via competitive endogenous RNA.

CT2-3 induces cell cycle arrest and apoptosis in rheumatoid arthritis fibroblast-like synoviocytes through regulating PI3K/AKT pathway

Rheumatoid arthritis (RA) is a kind of chronic autoimmune disease. The existing therapies encountered several challenges. Therefore, continued novel anti-RA drug discovery remains necessary for RA therapy. Recently, our group reported a novel compound named CT2-3, which could be realized as a hybrid of the natural product magnolol and phthalimide and exhibited anti-lung cancer activity. However, the effect of CT2-3 on RA is unclear. Here, we aim to explore the effect and potential mechanism of CT2-3 on the abnormal functions of RA-fibroblast-like synoviocytes (RA-FLSs). In this study, we identified the important role of the dysregulated cell cycle and apoptosis of RA-FLSs in RA progression. Interestingly, we found that CT2-3 inhibited the proliferation and DNA replication of primary RA-FLSs and immortalized RA-FLSs namely MH7A. In addition, CT2-3 downregulated the mRNA and protein expression of cyclin-dependent kinase 2 (CDK2), cyclin A2, and cyclin B1, resulting in cell cycle arrest of primary RA-FLSs and MH7A cells. Also, CT2-3 downregulated the level of B-cell lymphoma-2 (Bcl-2), and increased the level of Bcl-2 associated X (Bax), contributing to apoptosis of primary RA-FLSs and MH7A cells. Furthermore, differential analyses of RNA-sequencing, Western blot, and network pharmacological analysis confirmed that CT2-3 inhibited phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) pathway of primary RA-FLSs and MH7A cells. In conclusion, CT2-3 induces cell cycle arrest and apoptosis in RA-FLSs through modulating PI3K/AKT pathway, which may serve as a potential lead compound for further novel small molecule anti-RA drug development.

Small-molecule nanoprodrug with high drug loading and EGFR, PI3K/AKT dual-inhibiting properties for bladder cancer treatment

Bladder cancer (BCa) is one of the most common malignancies worldwide. Although multiple efforts have been made, the 5-year survival rate of patients with BCa remains unchanged in recent years. Overexpression of the epidermal growth factor receptor (EGFR) is found in ≈74% of BCa tissue specimens; however, current EGFR-based targeted therapies show little benefit for BCa patients, as the EGFR downstream pathways appear to be circumvented by other receptor tyrosine kinases (RTKs). In this study, two natural products are identified, namely triptolide (TPL) and hesperidin (HSP), that target and inhibit the EGFR and its downstream PI3K/AKT pathway in BCa. To synergistically combine triptolide and hesperidin, a succinic acid linker was employed to conjugate them and formed an amphiphilic TPL-HSP EGFR-targeting prodrug (THE), which further self-assembled to generate nanoparticles (THE NPs). These NPs allowed the EGFR-targeted delivery of the triptolide and hesperidin, and simultaneous inhibition of the EGFR and PI3K/AKT both in vitro and in vivo. This study provides a promising EGFR-targeted delivery approach with the dual inhibition of the EGFR and PI3K/AKT, while also exhibiting a high drug loading and low toxicity. Our formulation may be a suitable option to deliver natural products for BCa treatment by EGFR-targeted therapy.

Rhodiola rosea L. Extract, a Known Adaptogen, Evaluated in Experimental Arthritis

Rhodiola rosea L. extract (RSE) is mostly known for its adaptogen properties, but not for its antiarthritic activities, therefore monotherapy and combination with low-dose methotrexate (MTX) was studied. The collagen-induced arthritis (CIA) model was used to measure the functional score, and the change in hind paw volume (HPV). Both parameters had significant antiarthritic effects. Based on these preliminary results, an adjuvant arthritis (AA) model was further applied to assess another parameters. The experiment included these animal groups: healthy controls, untreated AA, AA administered with RSE (150 mg/kg b.w. daily, p.o.), AA administered by MTX (0.3 mg/kg b.w. twice a week, p.o.), and AA treated with the combination of RSE+MTX. The combination of RSE+MTX significantly reduced the HPV and increased the body weight. The combination significantly decreased HPV when compared to MTX monotherapy. The plasmatic levels of inflammatory markers (IL-6, IL-17A, MMP-9 and CRP) were significantly decreased by MTX+RSE treatment. The RSE monotherapy didn't influence any of the inflammatory parameters studied. In CIA, the RSE monotherapy significantly decreased the arthritic parameters studied. In summary, the combination of RSE and sub-therapeutic MTX was significantly effective in AA by improving inflammatory and arthritic parameters.

Identification and preliminary validation of synovial tissue-specific genes and their-mediated biological mechanisms in rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease. It is well known that the formation of positive feedback between synovial hyperplasia and inflammatory infiltration is intimately associated with the occurrence and development of RA. However, the exact mechanisms still remain unknown, making the early diagnosis and therapy of RA difficult. This study was designed to identify prospective diagnostic and therapeutic biomarkers, as well as their-mediated biological mechanisms in RA.

METHODS

Three microarray datasets (GSE36700, GSE77298 and GSE153015) and two RNA-sequencing datasets (GSE89408 and GSE112656) of synovial tissues, as well as three other microarray datasets (GSE101193, GSE134087 and GSE94519) of peripheral blood were downloaded for integrated analysis. The differently expressed genes (DEGs) were identified by "limma" package of R software. Then, weight gene co-expression analysis and gene set enrichment analysis were performed to investigate synovial tissue-specific genes and their-mediated biological mechanisms in RA. The expression of candidate genes and their diagnostic value for RA were verified by quantitative real-time PCR and receiver operating characteristic (ROC) curve, respectively. Relevant biological mechanisms were explored through cell proliferation and colony formation assay. The suggestive anti-RA compounds were discovered by CMap analysis.

RESULTS

We identified a total of 266 DEGs, which were mainly enriched in cellular proliferation and migration, infection and inflammatory immune signaling pathways. Bioinformatics analysis and molecular validation revealed 5 synovial tissue-specific genes, which exhibited excellent diagnostic value for RA. The infiltration level of immune cells in RA synovial tissue was significantly higher than that in control individuals. Moreover, preliminary molecular experiments suggested that these characteristic genes may be responsible for the high proliferation potential of RA fibroblast-like synoviocytes (FLSs). Finally, 8 small molecular compounds with anti-RA potential were obtained.

CONCLUSIONS

We have proposed 5 potential diagnostic and therapeutic biomarkers (CDK1, TTK, HMMR, DLGAP5, and SKA3) in synovial tissues that may contribute to the pathogenesis of RA. These findings may shed light on the early diagnosis and therapy of RA.

Friend or foe? The dual role of triptolide in the liver, kidney, and heart

Triptolide, a controversial natural compound due to its significant pharmacological activities and multiorgan toxicity, has gained much attention since it was isolated from the traditional Chinese herb Tripterygium wilfordii Hook F. However, in addition to its severe toxicity, triptolide also presents powerful therapeutic potency in the same organs, such as the liver, kidney, and heart, which corresponds to the Chinese medicine theory of You Gu Wu Yun (anti-fire with fire) and deeply interested us. To determine the possible mechanisms involved in the dual role of triptolide, we reviewed related articles about the application of triptolide in both physiological and pathological conditions. Inflammation and oxidative stress are the two main ways triptolide exerts different roles, and the cross-talk between NF-κB and Nrf2 may be one of the mechanisms responsible for the dual role of triptolide and may represent the scientific connotation of You Gu Wu Yun. For the first time, we present a review of the dual role of triptolide in the same organ and propose the possible scientific connotation of the Chinese medicine theory of You Gu Wu Yun, hoping to promote the safe and efficient use of triptolide and other controversial medicines.

Triptolide leads to hepatic intolerance to exogenous lipopolysaccharide and natural-killer-cell mediated hepatocellular damage by inhibiting MHC class I molecules

BACKGROUND

Tripterygium wilfordii Hook. F (TWHF) is used as a traditional Chinese medicine, called thunder god vine, based on its efficacy for treating inflammatory diseases. However, its hepatotoxicity has limited its clinical application. Triptolide (TP) is the major active and toxic component of TWHF. Previous studies reported that a toxic pretreatment dose of TP leads to hepatic intolerance to exogenous lipopolysaccharide (LPS) stimulation, and to acute liver failure, in mice, but the immune mechanisms of TP-sensitised hepatocytes and the TP-induced excessive immune response to LPS stimulation are unknown.

PURPOSE

To identify both the key immune cell population and mechanism involved in TP-induced hepatic intolerance of exogenous LPS.

STUDY DESIGN

In vitro and in vivo experiments were conducted to investigate the inhibitory signal of natural killer (NK) cells maintained in hepatocytes, and the ability of TP to impair that signal.

METHODS

Flow cytometry was performed to determine NK cell activity and hepatocyte histocompatibility complex (MHC) class I molecules expression; the severity of liver injury was determined based on blood chemistry values, and drug- or cell-mediated hepatocellular damage, by measuring lactate dehydrogenase (LDH) release. In vivo H-2K^b transduction was carried out using an adeno-associated viral vector.

RESULTS

Interferon (IFN)-γ-mediated necroptosis occurred in C57BL/6N mice treated with 500 μg TP/kg and 0.1 mg LPS/kg to induce fulminant hepatitis. Primary hepatocytes pretreated with TP were more prone to necroptosis when exposed to recombinant murine IFN-γ. In mice administered TP and LPS, the intracellular IFN-γ levels of NK cells increased significantly. Subsequent study confirmed that NK cells were activated and resulted in potent hepatocellular toxicity. In vivo and in vitro TP administration significantly inhibited MHC class I molecules in murine hepatocytes. An in vitro analysis demonstrated the susceptibility of TP-pretreated hepatocytes to NK-cell-mediated cytotoxicity, an effect that was significantly attenuated by the induction of hepatocyte MHC-I molecules by IFN-α. In vivo induction or overexpression of hepatocyte MHC-I also protected mouse liver against TP and LPS-induced injury.

CONCLUSION

The TP-induced inhibition of hepatocyte MHC-I molecules expression leads to hepatic intolerance to exogenous LPS and NK-cell mediated cytotoxicity against self-hepatocytes. These findings shed light on the toxicity of traditional Chinese medicines administered for their immunomodulatory effects.

Triptolide improves chondrocyte proliferation and secretion via down-regulation of miR-221 in synovial cell exosomes

BACKGROUND

Rheumatoid arthritis (RA), the most common type of inflammatory arthritis, can cause bone damage and disability. Triptolide, a prominent treatment for RA, has satisfactory anti-inflammatory effects. However, the mechanism of action of triptolide in RA remains unknown.

PURPOSE

This study aimed to explore the molecular mechanisms underlying triptolide-mediated improvements in RA and identify the miRNA pathway responsible for these effects.

METHODS

We identified various dysregulated miRNAs associated with RA by mining previously described microarray data and verified and screened these candidates using RT-qPCR. Hematoxylin-eosin staining was then applied to identify pathological changes in the affected joints, and cell counting kit-8 analysis and flow cytometry were employed to examine cell proliferation and apoptosis, respectively. Extracted exosomes were verified using transmission electron microscopy.

RESULTS

Our results revealed that the legs of rats with collagen-induced arthritis presented with obvious swelling and bone damage, a high degree of inflammatory cell infiltration into the synovium, and structural changes to the cartilage. Data mining identified 39 dysregulated miRNAs in these tissues, and RT-qPCR further refined these observations to highlight miR-221 as a potential RA biomarker. Subsequent evaluations revealed that fibroblast-like synovial (FLS) cells secrete Exs carrying dysregulated miR-221 in vitro. These Exs mediate miR-221 levels, inflammation, and TLR4/MyD88 signaling via their fusion with chondrocytes, leading to changes in chondrocyte growth and metabolic factor levels. Additionally, the addition of triptolide impaired miR-221 expression, cell proliferation, inflammatory factors, and the protein levels of TLR4/MyD88 in RA-FLS and promoted the apoptosis of FLS. The therapeutic effect of triptolide on miR-221 Exs was reversed by miR-221 inhibitor in both normal and RA FLS.

CONCLUSION

Our research shows that effective treatment with triptolide is mediated by its regulation of growth and secretory functions of chondrocytes via the inhibition of miR-221 secretion by FLS, providing a new target and natural medicinal candidate for future RA treatments.

Trends and frontiers in natural products for arthritis, 2000-2021: A bibliometric analysis

BACKGROUND

Arthritis has become one of the trouble diseases that upsets people. A growing number of studies have shown that natural products have great potential for the treatment of arthritis. However, few bibliometrics have been systematically studied in this area. This paper analyzes the literature data of natural products on the arthritis research, and the research hot spots and future research directions of the treatment of arthritis by natural products were explored.

METHOD

Through CiteSpace, VOSviewer software and Bibliometricx under the R language environment, the article and review literatures on the treatment of arthritis with natural drugs in the Web of Science core collection database were analyzed by bibliometric analysis.

RESULTS

On December 28, 2021, a total of 2102 records were retrieved, 81.69% publications were issued in 2012 to 2021, mainly in China-dominated Asian countries, with cooperation among countries. The analysis of the number of articles published by institutions shows that the number of articles published by China Academy of Chinese Medical Sciences is up to 82. Lu, Aiping and Smolen, JS are the authors with the highest citation frequency and co-citation frequency. Keywords analysis showed that the research of natural drugs mainly focused on gene expression, anti-inflammatory and other mechanisms and signaling pathways. With the progress of science and technology and the integration of multi-disciplines, the research on natural drugs for arthritis will be more in-depth and specific.

CONCLUSION

In this study, literature metrology analysis was conducted on natural products in the treatment of arthritis, in order to grasp the background, trends and frontiers of the research, and predict possible research hotspots in the future. It is expected to provide some reference value and direction for future scholars in this field.

The role of lncRNAs in regulation of DKD and diabetes-related cancer

Diabetes mellitus often results in several complications, such as diabetic kidney disease (DKD) and end-stage renal diseases (ESRDs). Cancer patients often have the dysregulated glucose metabolism. Abnormal glucose metabolism can enhance the tumor malignant progression. Recently, lncRNAs have been reported to regulate the key proteins and signaling pathways in DKD development and progression and in cancer patients with diabetes. In this review article, we elaborate the evidence to support the function of lncRNAs in development of DKD and diabetes-associated cancer. Moreover, we envisage that lncRNAs could be diagnosis and prognosis biomarkers for DKD and cancer patients with diabetes. Furthermore, we delineated that targeting lncRNAs might be an alternative approach for treating DKD and cancer with dysregulated glucose metabolism.

Natural medicines of targeted rheumatoid arthritis and its action mechanism

Rheumatoid arthritis (RA) is an autoimmune disease involving joints, with clinical manifestations of joint inflammation, bone damage and cartilage destruction, joint dysfunction and deformity, and extra-articular organ damage. As an important source of new drug molecules, natural medicines have many advantages, such as a wide range of biological effects and small toxic and side effects. They have become a hot spot for the vast number of researchers to study various diseases and develop therapeutic drugs. In recent years, the research of natural medicines in the treatment of RA has made remarkable achievements. These natural medicines mainly include flavonoids, polyphenols, alkaloids, glycosides and terpenes. Among them, resveratrol, icariin, epigallocatechin-3-gallate, ginsenoside, sinomenine, paeoniflorin, triptolide and paeoniflorin are star natural medicines for the treatment of RA. Its mechanism of treating RA mainly involves these aspects: anti-inflammation, anti-oxidation, immune regulation, pro-apoptosis, inhibition of angiogenesis, inhibition of osteoclastogenesis, inhibition of fibroblast-like synovial cell proliferation, migration and invasion. This review summarizes natural medicines with potential therapeutic effects on RA and briefly discusses their mechanisms of action against RA.

Overexpression of long noncoding RNA LINC00638 inhibits inflammation and oxidative stress in rheumatoid arthritis fibroblast-like synoviocytes by regulating the Nrf2/HO-1 pathway

BACKGROUND

Abnormal expression of long noncoding RNAs (lncRNAs) is involved in several autoimmune diseases including rheumatoid arthritis (RA). In this study, we intended to explore the expression of lncRNA LINC00638 in RA and its potential mechanism of action related to inflammation and oxidative stress.

METHODS

The level of LINC00638 in the peripheral blood mononuclear cells (PBMCs) obtained from 45 RA patients and 30 normal controls was analyzed and its correlation with clinical indicators was investigated. In vitro, we used tumor necrosis factor-α to stimulate fibroblast-like synoviocytes (FLS) of RA patients for cell based experiments. Subsequently, the overexpressed plasmid and small interfering RNA of LINC00638 were designed. Furthermore, we further analyzed the potential effects of LINC00638 on the proliferation and migration of RA-FLS and the nuclear factor erythrocyte derived 2 related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) pathway.

RESULTS

LINC00638 expression was found to be significantly decreased in PBMCs of RA patients, and it was negatively correlated with erythrocyte sedimentation rate, interleukin (IL)-17, reactive oxygen species (ROS), and disease activity scores for 28 joints (DAS28). Overexpression of LINC00638 activated the Nrf2/HO-1 pathway, markedly decreased the expressions of IL-6, IL-17, IL-23, ROS, as well as malondialdehyde, increased the total antioxidant capacity, and attenuated the proliferation and migration of RA-FLS, while silencing of LINC00638 reversed these manifestations.

CONCLUSIONS

LINC00638 was found to be expressed at low levels in RA patients and was associated with immune inflammation, oxidative stress, and disease activity. Overexpression of LINC00638 can reduce the proliferation as well as migration of RA-FLS, and activate the Nrf2/HO-1 pathway to inhibit the inflammation and oxidative stress.

[Triptolide inhibits inflammatory response and migration of fibroblast like synovial cells in rheumatoid arthritis through the circRNA 0003353/JAK2/STAT3 signaling pathway]

OBJECTIVE

To investigate the effect of triptolide (TPL) on inflammatory response and migration of fibroblast like synovial cells (FLS) in rheumatoid arthritis (RA-FLS) and the mechanism of circular noncoding RNA (circRNA) 0003353 for mediating this effect.

METHODS

We collected peripheral blood mononuclear cells (PBMCs) and serum samples from 50 hospitalized RA patients and 30 healthy individuals for detecting the expression of circRNA 0003353, immune and inflammatory indexes (ESR, CRP, RF, anti-CCP, IgA, IgG, IgM, C3, and C4) and DAS28 score. Cultured RA-FLS was treated with 10 ng/mL TPL and transfected with a circRNA 0003353 overexpression plasmid, and cell counting kit-8 (CCK-8) assay and Transwell assay were used to detect the changes in the viability and migration of the cells. Enzyme-linked immunosorbent assay (ELISA) was used to examine the cytokines IL-4, IL-6, and IL-17, and real-time fluorescence quantitative PCR (RT-qPCR) was performed to detect the expression of circRNA 003353; Western blotting was used to detect the expressions of p-JAK2, pSTAT3, JAK2 and STAT3 proteins in the treated cells.

RESULTS

The expression of circRNA 0003353 was significantly increased in PBMCs from RA patients and showed a good performance in assisting the diagnosis of RA (AUC=90.5%, P < 0.001, 95% CI: 0.83-0.98). CircRNA 0003353 expression was positively correlated with ESR, RF and DAS28 (P < 0.05). Treatment with TPL significantly decreased the expression of circRNA 0003353, suppressed the viability and migration ability, decreased the expressions of IL-6 and IL-17, and increased the expression IL-4 in cultured RA-FLS in a time-dependent manner (P < 0.01). TNF-α stimulation of RA-FLS significantly increased the ratios of p-JAK2/JAK2 and p-STAT3/STAT3, which were obviously lowered by TPL treatment (P < 0.01). TPL-treated RA-FLS overexpressing circRNA 0003353 showed significantly increased cell viability and migration ability with decreased IL-4 expression and increased IL-6 and IL-17 expressions and ratios of p-JAK2/ JAK2 and p-STAT3/STAT3 (P < 0.01).

CONCLUSION

The expression of circRNA 0003353 is increased in PBMCs in RA patients and in RA-FLS. TPL treatment can regulate JAK2/STAT3 signal pathway and inhibit the inflammatory response and migration of RA-FLS through circRNA 0003353.

LncRNAs and Rheumatoid Arthritis: From Identifying Mechanisms to Clinical Investigation

Rheumatoid arthritis (RA) is a systemic chronic autoinflammatory disease, and the synovial hyperplasia, pannus formation, articular cartilage damage and bone matrix destruction caused by immune system abnormalities are the main features of RA. The use of Disease Modifying Anti-Rheumatic Drugs (DMARDs) has achieved great advances in the therapy of RA. Yet there are still patients facing the problem of poor response to drug therapy or drug intolerance. Current therapy methods can only moderate RA progress, but cannot stop or reverse the damage it has caused. Recent studies have reported that there are a variety of long non-coding RNAs (LncRNAs) that have been implicated in mediating many aspects of RA. Understanding the mechanism of LncRNAs in RA is therefore critical for the development of new therapy strategies and prevention strategies. In this review, we systematically elucidate the biological roles and mechanisms of action of LncRNAs and their mechanisms of action in RA. Additionally, we also highlight the potential value of LncRNAs in the clinical diagnosis and therapy of RA.

Triptolide inhibits cell growth and inflammatory response of fibroblast-like synoviocytes by modulating hsa-circ-0003353/microRNA-31-5p/CDK1 axis in rheumatoid arthritis

Triptolide (TPL) is an active component derived from Tripterygium wilfordii Hook F (TwHF) with therapeutic potential for rheumatoid arthritis (RA). However, the underlying mechanism of TPL is remains under-studied. Competing endogenous RNA (ceRNA) networks may participate in the response to TPL in RA. Herein, we sought to identify a TPL response-related ceRNA axis. A circular RNA (circRNA)-microRNA (miRNA)-mRNA ceRNA axis associated with the TPL response was constructed according to our previous study. Modulatory mechanisms of the ceRNA axis were ascertained through a series of experimentations. The clinical relevance of the ceRNA axis was also determined using computational models. Here, we found that TPL had excellent clinical effect on RA and promising therapeutic efficacy in experimental animals. The ceRNA axis of hsa-circ-0003353 (circ0003353), miR-31-5p, and CDK1 was identified as a candidate biomarker for the response of RA patients to TPL. TPL inhibited the viability, proliferation, and cell cycle entry of RA-fibroblast-like synoviocytes (FLSs), as well as the production of cytokines. Overexpression of circ0003353 abolished the inhibitory effects of TPL on RA-FLSs. Mechanistically, circ0003353 sponged miR-31-5p that inversely targeted CDK1 and manipulated the p21/Cyclin B axis. Additionally, consecutive rescue experiments indicated that the inhibitory impacts of TPL on RA-FLSs were dependent on the circ0003353/miR-31-5p/CDK1 axis. Molecular docking was also applied to predict the specific binding sites and binding capacity of TPL to related targets. In conclusion, the present study demonstrated that TPL repressed the cell growth and inflammatory response of RA-FLSs by mediating the expression of the circ0003353/miR-31-5p/CDK1 axis. This novel ceRNA axis may serve as a biomarker for screening RA patients who respond to TPL treatment, which holds potential applications in the diagnosis and therapy of RA.