Apoptosis Of RA-FLS Research Articles

Sesamol serves as a p53 stabilizer to relieve rheumatoid arthritis progression and inhibits the growth of synovial organoids

BackgroundRheumatoid arthritis (RA) is an autoimmune disease known as a leading cause of disability with considerable mortality. Developing alternative drugs and targets for RA treatment is an urgent issue. Sesamol is a phenolic compound isolated from natural food sesame (Sesamum indicum L.) with various biological activities. PurposeThe current research intended to illuminate the bioactivity and mechanisms of sesamol in RA fibroblast-like synoviocytes (FLS), and aimed to estimate the potential clinical application value of sesamol in RA treatment. MethodsCCK-8, EdU, and flow cytometry assays, as well as transwell tests were applied to observe the effects of sesamol on the abnormal functions of RA-FLS. Moreover, synovial organoids and a collagen-induced arthritis (CIA) mouse model were constructed to further explore the therapeutic capacity of sesamol on RA. Furthermore, RNA sequencing combined with quantitative real-time PCR assay, Western blot as well as co-immunoprecipitation were employed to clarify the mechanism of sesamol in regulating RA progression. ResultsSesamol suppressed the proliferation through inhibiting DNA replication, triggering cell cycle arrest and apoptosis of RA-FLS. Besides, sesamol impaired RA-FLS migration and invasion. Interestingly, sesamol inhibited the growth of constructed synovial organoids and alleviated RA symptoms in CIA mice. Moreover, RNA sequencing further implicated p53 signaling as a downstream pathway of sesamol. Furthermore, sesamol was shown to decrease p53 ubiquitination and degradation, thereby activating p53 signaling. Finally, bioinformatics analyses also highlighted the importance of sesamol-regulated networks in the progression of RA. ConclusionsOur investigation demonstrated that sesamol served as a novel p53 stabilizer to attenuate the abnormal functions of RA-FLS via facilitating the activation of p53 signaling. Moreover, our study highlighted that sesamol might be an effective lead compound or candidate drug and p53 could be a promising target for the therapy of RA.

Icariin decreases cell proliferation and inflammation of rheumatoid arthritis-fibroblast like synoviocytes via GAREM1/MAPK signaling pathway

Objective Rheumatoid arthritis (RA) is an autoimmune disorder characterized by chronic inflammation and joint damage, leading to pain and reduced joint function. Icariin, a flavonoid compound, has been studied for its potential therapeutic role in RA due to its anti-inflammatory and anti-proliferative effects. Here, we aimed to investigate the action mechanism of icariin in regulating RA. Materials and methods Fibroblast-like synoviocytes (FLS) were obtained from RA and trauma patients, generating RA-FLS and normal FLS. The cells were treated with varying concentrations of icariin (0, 10, 20, 40, 80 μM). We assessed the effects of icariin on cell proliferation, apoptosis, and levels of inflammatory factors using the CCK-8 assay, flow cytometry, and enzyme-linked immunosorbent assay, qRT-PCR, and western blotting. Results Icariin treatment had no significant impact on the cell proliferation of normal FLS. However, it dose-dependently repressed cell proliferation, reduced TNF-α, IL-6, and IL-1β levels, and increased apoptosis in RA-FLS. The expression of GAREM1, p-p38, and p-ERK1/2 was upregulated in RA-FLS, which was reversed by icariin treatment. Overexpression of GAREM1 reversed the inhibitory effects of icariin on cell proliferation and inflammatory factor levels in RA-FLS. Conclusion Our findings suggest that icariin treatment can alleviate the development of RA by reducing cell proliferation and inflammation in RA-FLS through the regulation of the GAREM1/MAPK signaling pathway. These results support the potential of icariin as a therapeutic agent for RA treatment. As icariin is safe and well-tolerated in previous studies, further research is warranted to explore its efficacy in clinical settings.

IL-37 alleviates TNF-α-induced pyroptosis of rheumatoid arthritis fibroblast-like synoviocytes by inhibiting the NF-κB/GSDMD signaling pathway

ObjectivePyroptosis is crucial to rheumatoid arthritis (RA) by inducing and aggravating inflammation. TNF-α is abundant in fibroblast-like synoviocytes of RA (RA-FLSs) and plays a key role in pyroptosis by inducing nuclear factor (NF)-κB activation. Additionally, interleukin (IL)-37 is involved in autoimmune diseases as an anti-inflammatory cytokine and innate and acquired immune response inhibitor. However, the effect of IL-37 on pyroptosis in RA-FLSs remains unclear. Therefore, this study investigated the effects and mechanism of IL-37 on RA-FLS pyroptosis induced by TNF-α. MethodsIn this study, the serum cytokines in patients with RA and healthy controls were detected using ELISA. The RA-FLSs were then cultured with TNF-α, with or without various IL-37 concentrations, to test the cytokine levels in the cell supernatant. 5-Ethynyl-2ʹ-Deoxyuridine (EdU) assay assessed the effects of IL-37 on RA FLS proliferation. RA-FLS apoptosis was assessed using flow cytometry and mitochondrial membrane potential (MMP) measurement. In addition, transmission electron microscopy (TEM) was used to examine cell pyroptosis. We selected the optimal concentration for the following experiments and detected the signal pathway of IL-37 on pyroptosis of RA FLSs by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and Western blotting. Finally, we validated the therapeutic effects of IL-37 on CIA rat model in vivo. ResultsIL-37 inhibited inflammation in vitro and in vivo and reduced pyroptosis-related protein expression in RA FLSs. Furthermore, we determined that nuclear factor κB (NF-κB) signaling is required for GSDMD-mediated pyroptosis in RA FLSs. ConclusionIL-37 alleviates TNF-α-induced pyroptosis of RA FLSs by inhibiting NF-κB/GSDMD signaling. Additionally, our data revealed a novel mechanism for IL-37 in RA FLSs, suggesting a new potential therapy for IL-37 to treat RA.

MiR-361-5p promotes proliferation and inhibits apoptosis of fibroblast-like synoviocytes via targeting ZBTB10 in rheumatoid arthritis

Objectives This study is aimed to explore the key role of miR-361-5p in fibroblast-like synovial (FLS) cells of rheumatoid arthritis (RA) and explore the underlying mechanism. Methods First, we performed RT-qPCR to evaluate the expression of miR-361-5p in both synovial tissues of RA patients and cultured RA-FLS cells. Then CCK-8 assay, EdU staining, Western blot, flow cytometry, and ELISA were conducted to estimate the influence of inhibiting miR-361-5p on RA-FLS cells. Moreover, we used bioinformatics analysis to predict the potential targets of miR-361-5p and perform a dual luciferase report assay for verification. Finally, rescue experiments were performed to prove the role of miR-361-5p/Zinc Finger And BTB Domain Containing 10 (ZBTB10) in the proliferation, cell cycle, and apoptosis of RA-FLS. Results We find that the expression of miR-361-5p is increased in both RA tissues and cultured RA-FLS cells. The inhibition of miR-361-5p can not only inhibit proliferation, arrest the cell cycle in G1/G0 phase, and increase apoptosis, but also reduce the inflammatory factors secreted by RA-FLS cells. In addition, ZBTB10 is a direct target for miR-361-5p, over-expression of ZBTB10 reverses the effect of miR-361-5p in RA-FLS. Conclusions MiR-361-5p promotes the progression of rheumatoid arthritis by targeting ZBTB10. Key points The influences of miR-361-5p on RA-FLS cells.

Xinfeng Capsules promotes apoptosis of synovial fibroblasts and attenuates inflammation in rheumatoid arthritis by regulating lncRNA MAPKAPK5-AS1

To explore the regulatory effects of Xinfeng Capsules(XFC) on the apoptosis of synovial fibroblasts(FLS) and inflammation in rheumatoid arthritis(RA) via lncRNA MAPKAPK5-AS1(MK5-AS1). Thirty healthy people and 30 patients with RA due to spleen deficiency and dampness exuberance were collected for extracting the peripheral blood mononuclear cells(PBMCs) before and after XFC treatment, which were used to observe the correlation between MK5-AS1 and clinical indicators as well as MK5-AS1 expression before and after XFC treatment. Following the establishment of RA-FLS cell line and the preparation of XFC-containing serum, MK5-AS1-overexpression plasmid was constructed and transfected into RA-FLS for investigating the efficacy of XFC-containing serum in regulating inflammation and apoptosis of RA-FLS via MK5-AS1. The expression of MK5-AS1 in PBMCs of patients with RA due to spleen deficiency and dampness exuberance was decreased(P<0.001). The ROC curve analysis revealed the AUC of 83.9%. Correlation analysis showed that MK5-AS1 was negatively correlated with ESR, CRP, RF, CCP, and spleen deficiency and dampness exuberance syndrome score. The expression of MK5-AS1 increased significantly after XFC treatment(P<0.001). As demonstrated by association analysis, XFC decreased MK5-AS1, ESR, CRP, RF, and spleen deficiency and dampness exuberance syndrome score, with the degree of support all greater than 83%, confidence greater than 80%, and lift greater than 1. The results of RT-qPCR showed that the MK5-AS1 RNA expression significantly decreased after TNF-α stimulation(P<0.01), which, however, increased significantly after the intervention with XFC-containing serum(P<0.05). Such expression rose again after the transfection of pcDNA3.1-MK5-AS1(P<0.01). ELISA results showed that TNF-α stimulation elevated the expression of pro-inflammatory factor IL-17 but lowered the expression of anti-inflammatory factor IL-4(P<0.01). After intervention with XFC-containing serum, the expression of IL-17 decreased while that of IL-4 increased(P<0.01). The transfection of pcDNA3.1-MK5-AS1 contributed to the reduction in IL-17 expression but the elevation in IL-4 expression(P<0.01). The immunofluorescence(IF) findings demonstrated that the expression of pro-apoptotic protein Bax was down-regulated, whereas that of the anti-apoptotic protein Bcl-2 was up-regulated after TNF-α stimulation(P<0.01). After the intervention with XFC-containing serum, the Bax expression was increased, while Bcl-2 expression was decreased(P<0.01), which were remarkably collaborated by the transfection of pcDNA3.1-MK5-AS1(P<0.05). The expression of MK5-AS1 is significantly decreased in both RA-PBMCs and RA-FLS, implying that XFC inhibits inflammatory reaction and promotes the apoptosis in RA by regulating the expression of MK5-AS1.

N6-methyladenosine modification of TGM2 mRNA contributes to the inhibitory activity of sarsasapogenin in rheumatoid arthritis fibroblast-like synoviocytes

BackgroundDeveloping alternative targets and drugs for rheumatoid arthritis (RA) treatment is currently an urgent issue. The relationship between TGM2 and the abnormal immune microenvironment in synovium tissues, as well as the specific role of TGM2 in RA are yet to be elucidated. Sarsasapogenin (Sar) is a sapogenin extracted from the Chinese medical herb Anemarrhena asphodeloides Bunge. and served as a representative anti-inflammatory drug capable of ameliorating inflammatory responses in several human diseases. However, the therapeutic effect of Sar on RA remains unknown. PurposeThis investigation aims to elucidate the role of TGM2 in RA and investigate whether Sar is a candidate drug to target TGM2 of fibroblast-like synoviocytes (FLS). MethodsBioinformatics analyses were applied for elucidating the role of N(6)-methyladenine (m6A) RNA methylation in RA and identifying the specific target regulated by m6A methylation in RA-FLS. Methylated RNA immunoprecipitation, CCK8 assay, Edu assay, flow cytometry, RT-qPCR and Western blot were utilized to investigate the function of Sar and TGM2 in RA-FLS. ResultsBioinformatics analyses emphasized the importance of m6A RNA methylation in RA and identified an m6A methylation-mediated gene TGM2. Interestingly, both m6A RNA methylation and TGM2 expression in RA synovium tissues correlated with activated immuno-inflammatory phenotype and associated with clinical characteristics and therapy response of RA patients. TGM2 served as a promoter of RA-FLS proliferation by inducing DNA replication and cell cycle transition and inhibiting apoptosis through activating NF-κB signaling. Intriguingly, Sar could impair m6A methylation of TGM2 mRNA and downregulate TGM2 expression. Downregulated TGM2 contributed to the suppressive role of Sar in DNA replication and the stimulatory role of Sar in cell cycle arrest and apoptosis of RA-FLS. Mechanically, Sar inhibited the expression of key regulators in DNA replication, cell cycle, and apoptosis by impairing NF-κB signaling, thus abolishing FLS proliferation to ameliorate RA progression. ConclusionsThis cross-validated work based on three independent datasets is detailedly delineated using cell lines and clinical samples, recognizing that TGM2 can be an attractive target and Sar might be a novel anti-RA drug.

Paclitaxel Inhibits Synoviocyte Migration and Inflammatory Mediator Production in Rheumatoid Arthritis

Activated fibroblast-like synoviocytes (FLSs) play a crucial role in the pathogenesis and progression of rheumatoid arthritis (RA). It is urgent to develop new drugs that can effectively inhibit the abnormal activation of RA-FLS. In our study, the RA-FLS cell line, MH7A, and mice with collagen-induced arthritis (CIA) were used to evaluate the effect of paclitaxel (PTX). Based on the results, PTX inhibited the migration of RA-FLS in a dose-dependent manner and significantly reduced the spontaneous expression of IL-6, IL-8, and RANKL mRNA and TNF-α-induced transcription of the IL-1 β, IL-8, MMP-8, and MMP-9 genes. However, PTX had no significant effect on apoptosis in RA-FLS. Mechanistic studies revealed that PTX significantly inhibited the TNF-α-induced phosphorylation of ERK1/2 and JNK in the mitogen-activated protein kinase (MAPK) pathway and suppressed the TNF-α-induced activation of AKT, p70S6K, 4EBP1, and HIF-1α in the AKT/mTOR pathway. Moreover, PTX alleviated synovitis and bone destruction in CIA mice. In conclusion, PTX inhibits the migration and inflammatory mediator production of RA-FLS by targeting the MAPK and AKT/mTOR signaling pathways, which provides an experimental basis for the potential application in the treatment of RA.

MicroRNA-16-5p Promoted Fibroblast-Like Synoviocyte Proliferation and Suppressed Apoptosis via Targeting Suppressor of Cytokine Signaling 6 (SOCS6) in Human Rheumatoid Arthritis

Accumulating evidence have indicated that MicroRNAs (miRNAs) are key regulators in human rheumatoid arthritis (RA). The aim of this study was to explore the functional roles of miR-16-5p in proliferation, inflammation, and apoptosis of fibroblast-like synoviocytes (FLS). The expression of miR-16-5p and SOCS6 in FLA was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation and apoptosis were measured by CCK-8 assay and flow cytometry, respectively. Luciferase reporter assay was used to verify the direct target of miR-16-5p. Western blot analysis was performed to analysis the levels of SOCS6, Bcl-2, Bax and cleaved caspase 3. miR-16-5p expression was significantly upregulated while SOCS6 level was decreased in RA-FLS compared with normal FLS. In addition, luciferase reporter assay confirmed that SOCS6 was the target of miR-16-5p. Silencing of miR-16-5p inhibited cell proliferation, releases of TNF-α, IL-1β, IL-6 and IL-8, and induced the apoptosis. The effects of miR-16-5p silencing on RA-FLS were reversed by downregulation of SOCS6. In summary, knockdown of miR-16-5p could suppress cell proliferation and accelerate the apoptosis of RA-FLS through targeting SOCS6, which may provide a potential therapeutic target for patients with RA.

Resveratrol promotes apoptosis and G2/M cell cycle arrest of fibroblast-like synoviocytes in rheumatoid arthritis through regulation of autophagy and the serine-threonine kinase-p53 axis.

Resveratrol, a polyphenol extracted from many plant species, has emerged as a promising pro-apoptotic agent in various cancer cells. However, the role of resveratrol in cell proliferation and apoptosis of fibroblast-like synoviocytes in rheumatoid arthritis (RA-FLS) is not fully understood. The study was aimed at elucidating the role of resveratrol in cell proliferation and apoptosis of RA-FLS and the underlying molecular mechanism. Cultured RA-FLSs were subjected to tumour necrosis factor α (TNF-α). The cell proliferation was measured by Cell Counting Kit-8 assay. Cell apoptosis and cell cycle of RA-FLSs were determined by flow cytometry. The levels of apoptosis or autophagy or cell cycle-related protein were detected by immunoblot analysis. In our study, we confirmed that resveratrol reversed TNF-α mediated cell proliferation in RA-FLS. Meanwhile, resveratrol blocked cells at the G2/M stage and reduced the ratio of S phase cells through upregulation of p53 and consequently led to apoptotic cell death. Quite interestingly, we found that resveratrol reversed TNF-α-induced autophagy. Inhibition of autophagy by resveratrol or autophagy inhibitor or Beclin-1 siRNA suppressed TNF-α mediated cell survival and promoted cell apoptosis. However, the autophagy inducer rapamycin (RAPA) reversed the effect of resveratrol on autophagy and cell proliferation. Mechanistic studies revealed that resveratrol inhibited the activation of the phosphoinositide 3-kinases/serine-threonine kinase (PI3K/AKT) pathway. Inhibition of PI3K/AKT pathway by inhibitor LY294002 or resveratrol increased the expression of p53 and decreased the expression of cycle protein (cyclin B1), which further led to block cells in the G2/M arrest. Our preliminary study indicated that resveratrol may suppress RA-FLS cell survival and promote apoptosis at least partly through regulation of autophagy and the AKT-p53 axis.

Effect of Xinfeng Capsules-containing serum on TNF-α-induced apoptosis and inflammation of fibroblast-like synoviocytes in rheumatoid arthritis

The aim of this paper was to observe the effect of Xinfeng Capsules(XFC)-containing serum on the apoptosis and inflammation of fibroblast-like synoviocytes(FLS) in rheumatoid arthritis(RA) induced by tumor necrosis factor-α(TNF-α), so as to investigate the mechanism of XFC in the treatment of RA. RA-FLS immortalized cell line was established, and XFC drug-containing serum was prepared. CCK-8, ELISA, RT-qPCR, immunofluorescence and TUNEL were used to observe the effect of XFC-containing serum on RA-FLS apoptosis and inflammatory indexes. CCK-8 results showed that the optimal concentration and time of TNF-α on RA-FLS were 10 ng·mL~(-1) and 48 h, respectively; and the optimal concentration and time of XFC on RA-FLS were 6.48 mg·g~(-1) and 72 h, respectively. The results of ELISA showed that compared with RA-FLS group, the expressions of TNF-α, IL-1β, IL-6, IL-8 in TNF-α+RA-FLS group were significantly increased, while the expressions of IL-4 and IL-10 were significantly decreased(P<0.01); after intervention with XFC-containing serum, the expressions of TNF-α, IL-1β, IL-6, IL-8 were significantly decreased, whereas the expressions of IL-4 and IL-10 were significantly increased(P<0.01). The results of RT-qPCR showed that compared with RA-FLS group, the mRNA expressions of Fas, FasL, caspase-3, caspase-8, Bax, Bcl-X1 in TNF-α+RA-FLS group were significantly decreased, while the mRNA expression of Bcl-2 was significantly increased(P<0.001); after intervention with XFC-containing serum, the mRNA expressions of Fas, FasL, caspase-3, caspase-8, Bax, Bcl-X1 were significantly increased, whereas the mRNA expression of Bcl-2 was significantly decreased(P<0.01). The results of immunofluorescence showed that compared with RA-FLS group, the protein expressions of caspase-3 and Bax in TNF-α+RA-FLS group was significantly lower than those in RA-FLS group(P<0.05); after intervention with XFC-containing serum, the protein expressions of caspase-3 and Bax were significantly increased, whereas the protein expression of Bcl-2 was significantly decreased(P<0.05). TUNEL results showed that compared with RA-FLS group, the apoptosis of TNF-α+RA-FLS group was decreased(P<0.05); after intervention with XFC-containing serum, the apoptosis was significantly increased(P<0.05). One of the mechanisms of XFC in the treatment of RA is to promote the apoptosis of RA-FLS and inhibit its inflammatory reaction.

MicroRNA-34a Promotes Apoptosis of Rheumatoid Arthritis Fbroblast-Like Synoviocyte via AMPK/Akt/mTOR Signaling Pathway

Background and Objectives: Rheumatoid arthritis (RA) is an autoimmune arthropathy characterised by chronic synovitis, joint cartilage breakdown and bone erosions. The life quality of RA patients has been substantially effected by the disease and it is of great significance to search for more efficacious and novel therapeutic agents. Methods: In this study, mRNA levels of miR-34a in HFLS and RA-FLS were examined by RT-PCR. CCK8 assay was applied to detect the viability of RA-FLS transfected with miR-34a mimic or inhibitor. Furthermore, TUNEL assay and Hoechest-33342 assay was applied to detect the apoptosis of RA-FLS transfected with miR-34a mimic or inhibitor. The expressions of proteins related to AMPK/Akt/mTOR and autophagy were also detected by western blot. Results: The RT-PCR result showed that miR-34a mRNA levels was markedly downregulated in RA-FLS compared to HFLS. CCK8 assay results demonstrated that miR-34a overexpression significantly suppressed RA-FLS proliferation and miR-34a interference had the opposite effect. TUNEL assay and Hoechest-33342 assay demonstrated that miR-34a overexpression significantly promoted RA-FLS apoptosis and miR-34a interference had the opposite effect. The western blot results revealed that miR-34a can affect autophagy via AMPK/Akt/mTOR signaling pathway. Conclusion: This study suggested that miR-34a can regulate proliferation and apoptosis in RA-FLS by affecting autophagy through AMPK/Akt/mTOR signaling pathway.

The Role of miR-382-5p in Rheumatoid Arthritis: An In Vitro Study with Fibroblast-Like Synoviocytes

Rheumatoid arthritis (RA) is a common autoimmune inflammatory disease with high morbidity. MiR-382-5p may be associated with progression from systemic autoimmunity to RA inflammation. The present study aims to investigate the underlying mechanism of miR-382-5p in the pathogenesis of RA. In present study, the decreased expression of miR-382-5p was observed in RA-FLSs. Furthermore, miR-382-5p overexpression inhibited the proliferation and invasion of RA-FLS cells. In addition, miR-382-5p overexpression inhibited the release of inflammatory cytokines and promoted apoptosis of RA-FLS cells. Finally, miR-382-5p overexpression induced inactivation of TLR4/NF-κB/Cox2 signaling pathway. Our findings implied that miR-382-5p exerts regulative effect on pathogenesis of RA and indicated that miR-382-5p may represent as an effective therapeutic target in the clinical treatment of RA.

Diallyl Trisulfide can induce fibroblast-like synovial apoptosis and has a therapeutic effect on collagen-induced arthritis in mice via blocking NF-κB and Wnt pathways

BackgroundDiallyl Trisulfide (DATS) is an organosulfur compound extracted from garlic bulb, and exerts cardioprotective, anti-inflammatory, antioxidant, antimicrobial and anticancer effects. But its role in the pathogenesis of rheumatoid arthritis (RA) is unknown. Here we explored the influence of DATS on human fibroblast-like synoviocytes (FLS) isolated from RA patients and a mouse model of collagen-induced arthritis (CIA) and the underlying mechanism. MethodsRA-FLS were cultured and treated with different concentrations of DATS. The CCK8 assay was used to assess cell proliferation while cell apoptosis was detected by flow cytometry and western blot. The IL-8, IL-6 and IL-1β levels were determined using RT-qPCR and ELISA assay. The expression of proteins of the NF-κB and Wnt pathways were measured using western blot. Furthermore, the effect of DATS was also explored in vivo using the collagen-induced arthritis mouse model. The Th17/Treg pattern obtain from cells of spleen of collagen-induced arthritis mouse model was detected by flow cytometry. ResultsOur results showed that DATS could decrease cell viability and introduce apoptosis in RA-FLS. Furthermore, DATS significantly attenuated the production of key inflammatory cytokines induced by RA-FLS cells following treatment with tumor necrosis α (TNF-α) at a concentration of 100 μM or higher. This was due to its inhibitory effect on the NF-κB and Wnt pathway signaling in RA-FLS. Additionally, DATS decreased the production of inflammatory cytokines and regulated the immune function by restoring the balance between Th17 and Treg in CIA mouse model. ConclusionsIn conclusion, DATS may serve as a potential curative agent for RA.

MiR-199a-3p inhibits proliferation and induces apoptosis in rheumatoid arthritis fibroblast-like synoviocytes via suppressing retinoblastoma 1.

Background Fibroblast-like synoviocytes (FLSs) that line the intimal synovium play a crucial role in the pathogenesis of rheumatoid arthritis (RA). miR-199a-3p is a highly conserved miRNA that has been shown to regulate a variety of growth behaviors in diverse cell types. However, the role of miR-199a-3p in RA-FLS is still unknown. Methods Here, we presented the first experimental evidence showing that miR-199a-3p was a critical regulator of RA-FLS function. Results miR-199a-3p expression was significantly reduced in RA-FLS compared with normal FLS. Ectopic expression of miR-199a-3p significantly inhibited RA-FLS proliferation and induced apoptosis, which was demonstrated by an increase in caspase-3 activity and Bax/Bcl-2 ratio. Our bioinformatics analysis identified Retinoblastoma 1 (RB1) gene to be a direct target of miR-199a-3p. In RA-FLS, miR-199a-3p directly targetted the 3′-UTR of RB1 mRNA and suppressed endogenous RB1 expression, whereas miR-199a-3p-resistant variant of RB1 was not affected. Silencing RB1 decreased cell proliferation and promoted apoptosis in RA-FLS, an effect comparable with miR-199a-3p overexpression. Enforced expression of RB1 partially restored cell proliferation and attenuated apoptosis in miR-199a-3p-overexpressing RA-FLSs. Conclusion In summary, miR-199a-3p is down-regulated in RA-FLS, and miR-199a-3p inhibits proliferation and induces apoptosis in RA-FLS, partially via targetting RB1. The miR-199a-3p/RB1 pathway may represent a new therapeutic target for RA.

MiR-212-3p reduced proliferation, and promoted apoptosis of fibroblast-like synoviocytes via down-regulating SOX5 in rheumatoid arthritis.

Several microRNAs have been reported to contribute the progression of rheumatoid arthritis (RA) due to the ectopic expression of miRNAs in fibroblast-like synoviocytes (FLS). However, the function of miR-212-3p in RA still has not been mentioned before. We obtained serum, synovial tissues, and FLS samples from RA patients and normal donors. Quantitative Real-time polymerase chain reaction (qRT-PCR) was used to analysis the expression level of miR-212-3p. By using miR-212-3p mimics and inhibitors, we detected the effects of miR-212-3p on cell proliferation, cell cycle, and apoptosis in RA-FLS. Dual-luciferase and Western-blot were employed to verify the target of miR-212-3p. In addition, we over-expressed the SOX5 in miR-212-3p mimics treatment FLS to emphasize our results. The level of miR-212-3p in serum, synovial tissues, and FLS from RA patients was lower than these in relative normal group. Up-regulation of miR-212-3p inhibited cell proliferation, promoted cell apoptosis; however, knockdown of miR-212-3p promoted cell growth but reduced cell apoptotic rate. Furthermore, we found SOX5 as a direct target of miR-212-3p in RA-FLS and up-regulation of SOX5 reversed the effects of miR-212-3p over-expression. miR-212-3p could reduce cell proliferation and promoted cell apoptosis of RA-FLS via repressing SOX5, which may provide a new biological target for RA treatment.

P26 Tamaractam, a natural lactam, induces apoptosis and inhibits inflammation in rheumatoid arthritis fibroblast-like synoviocytes

Tamaractam is a novel lactam isolated from Tamarix ramosissima Ledeb., a traditional herbal medicine used for rheumatoid arthritis (RA) treatment in northwest China. The present study investigated the pro-apoptotic and anti-inflammatory effects of tamaractam on fibroblast-like synoviocytes (FLS) from RA patients. Apoptosis was assessed by TUNEL assay and caspase-3 activity was assessed by a colorimetric assay. The expression levels of apoptosis-related proteins including Bcl-2, Bax, p-Akt and p53 were determined by western blot analyses. The levels of IL-1β, IL-6, MMP-9 and COX-2 were measured using ELISA, and the mRNA expressions of these pro-inflammatory mediators were measured with quantitative real-time PCR. Tamaractam (0.1 and 1 μM) treatment induced cellular apoptosis of RA-FLS and also resulted in a significant increase in caspase-3 activity. It was found that tamaractam could regulate the protein expression of Bcl-2, Bax, p53 and pAkt. The concentrations and mRNA expression levels of IL-1β, IL-6, MMP-9 and COX-2 from RA-FLS were suppressed by tamaractam treatment in a dose-dependent manner. In conclusion, tamaractam treatment was found to induce apoptosis of RA-FLS through regulation of apoptosis related protein expression and to reduce the level of pro-inflammatory factors through inhibition of pro-inflammatory gene expression in RA-FLS. These results suggest that the pro-apoptotic and anti-inflammatory activities of tamaractam may be used as a possible therapeutic option for RA.

Therapeutic effects of matrine derivate MASM in mice with collagen-induced arthritis and on fibroblast-like synoviocytes

MASM is a matrine derivate that exhibits a number of pharmacological effects, including immunosuppressive activity and anti-inflammatory properties. In this study, the mechanisms underlying the therapeutic efficacy of MASM in the treatment of rheumatoid arthritis were investigated using DBA/1 mice with collagen-induced arthritis (CIA) and fibroblast-like synoviocytes derived from rheumatoid arthritis patients (RA-FLS). We demonstrated that MASM markedly attenuated the severity of arthritis in CIA mice. The therapeutic effects were associated with ameliorated joint swelling and reduced bone erosion and destruction. Furthermore, the administration of MASM suppressed the expression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6). In vitro, MASM inhibited the expression of pro-inflammatory cytokines (TNF-α, IL-6, IL-8) and matrix metalloproteinases (MMP-1, MMP-3 and MMP-13) by inhibiting both the phosphorylation of MAPKs and the activation of NF-κB in IL-1β-stimulated RA-FLS. Additionally, MASM could induce apoptosis of RA-FLS via mitochondrial and Akt signaling pathways in human RA-FLS. These findings suggest that MASM could attenuate arthritis severity in CIA mice at least partially by blocking the phosphorylation of MAPKs and the activation of NF-κB and by inducing apoptosis in RA-FLS. MASM could be a potent therapeutic agent for the treatment of RA.

Dishevelled2 promotes apoptosis and inhibits inflammatory cytokine secretion in rheumatoid arthritis fibroblast-like synoviocytes through crosstalk with the NF-κB pathway.

Dishevelled (Dvl) not only links the canonical Wnt and non-canonical Wnt pathways but can also crosstalk with other pathways. As there is no systematic study to date on Dvl in rheumatoid arthritis (RA), we explored the impact of Dvl2 on proliferation and inflammatory cytokine secretion in RA fibroblast-like synoviocytes (FLSs). Expression of Dvl2 in RA synovial tissue and RA-FLSs was measured. Dvl2 was overexpressed in collagen-induced arthritis rats and human RA-FLSs,. the apoptosis and secretion of inflammatory cytokines were observed. Genetic changes and corresponding mechanisms caused by overexpressing Dvl2 in RA-FLSs were assessed. Dvl2 was found to be overexpressed in RA synovial tissue and RA-FLSs. Overexpression of Dvl2 increased apoptosis and inhibited inflammatory cytokine secretion by RA-FLSs in vivo and in vitro, and Dvl2 inhibited expression of anti-apoptotic and inflammatory genes. One possible mechanism is that Dvl2 decreases the nuclear translocation of P65 and inhibits its ability to bind to the promoters of NF-κB target genes. Our findings reveal an underappreciated role of Dvl2 in regulating inflammation and RA-FLS apoptosis and provide insight into crosstalk between the Wnt and nuclear factor-κB (NF-κB) pathways.

Anti-apoptotic effect of interleukin-22 on fibroblast-like synoviocytes in patients with rheumatoid arthritis is mediated via the signal transducer and activator of transcription 3 signaling pathway.

Inadequate apoptosis of fibroblast-like synoviocytes (FLS) plays a crucial role in the immunopathogenesis of rheumatoid arthritis (RA). Interleukin-22 (IL-22) is a novel member of the cytokine network that has been found to be involved in the immunological process underlying RA. In this study, we investigated the effect of IL-22 on the survival of RA-FLS from RA patients and examined the possible mechanism to determine new therapeutic strategies for RA. FLS obtained from patients with RA were cultured in vitro and treated with sodium nitroprussiate (SNP) to induce apoptosis in the presence or absence of IL-22. RA-FLS viability was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. RA-FLS apoptosis was analyzed by annexin V/propidium iodide staining (AV/PI). The levels of IL-22R1, pSTAT3-Y705, pSTAT3-S727, total STAT3, Bcl-xL and Bcl-2 were detected by Western blot analysis. IL-22R1 was expressed on RA-FLS. IL-22 pretreatment at concentrations ranging from 10 to 100 ng/mL increased RA-FLS viability and prevented SNP-induced apoptosis. Treatment with the STAT3 inhibitors, HO3867 or STA21, reversed the protective effect of IL-22 on SNP-induced apoptosis of RA-FLS. IL-22-induced phosphorylation of STAT3 (pSTAT3-Y705 and pSTAT3-S727) was increased in RA-FLS. Also IL-22 increased Bcl-2 expression in SNP-treated RA-FLS, and the effect was reversed by treatment with HO3867 or STA21. IL-22 protects against SNP-induced apoptosis in RA-FLS by activating the STAT3 pathway and the downstream target gene, Bcl-2. Therefore, therapeutic strategies that target the IL-22/STAT3 pathway are implicated as candidates for RA treatment.

Down-regulating peroxisome proliferator-activated receptor-gamma coactivator-1 beta alleviates the proinflammatory effect of rheumatoid arthritis fibroblast-like synoviocytes through inhibiting extracellular signal-regulated kinase, p38 and nuclear factor-kappaB activation.

IntroductionRheumatoid arthritis (RA) is a chronic inflammatory disease leading to joint destruction and disability. Peroxisome proliferator-activated receptor-gamma coactivator-1beta (PGC-1β) is a transcriptional coactivator that plays important roles in regulating multiple aspects of energy metabolism and cytokine signaling pathways. PGC-1β overexpression leads to the attenuation of macrophage-mediated inflammation. In this study, we aimed to determine the expression of PGC-1β in RA synovium and fibroblast-like synoviocytes (FLS), and explore the mechanisms of PGC-1β on both the proinflammatory effects and apoptosis in RA-FLS.MethodsSynovium was obtained from 31 patients with active RA, as well as 13 osteoarthritis (OA) and 10 orthopedic arthropathies (Orth.A) as “less inflamed” disease controls. FLS were then isolated and cultured. Synovial PGC-1β expression was determined by immunohistochemistry staining, while FLS PGC-1β expression was detected by immunofluorescence staining, quantitative real-time PCR (qPCR) assay and western blot. PGC-1β was depleted by lentivirus sh-RNA, and up-regulated by pcDNA3.1- PGC-1β. The expression of proinflammatory cytokines, matrix metalloproteinases and receptor activator of nuclear factor-kappaB ligand was analyzed by qPCR, cytometric bead array and western blot. The expression of mitogen-activated protein kinases and nuclear factor-kappaB (NF-κB) was determined by qPCR and western blot. Besides, cell apoptosis was examined using flow cytometry. The interaction between PGC-1β and NF-κB was performed by dual-luciferase reporter gene assays.Results(A) Synovial PGC-1β was over-expressed in RA patients compared with OA or Orth.A patients. (B) PGC-1β expression significantly increased in RA-FLS compared with OA-FLS. (C) PGC-1β mediated the expression of proinflammatory cytokines and apoptosis through extracellular signal-regulated kinase (ERK), p38 and NF-κB in RA-FLS. (D) PGC-1β mediated NF-κB transcription in RA-FLS, but did not affect ERK and p38.ConclusionThe results indicate that PGC-1β may play important roles in the proinflammatory effects and apoptosis of RA-FLS.