Apoptosis of rheumatoid arthritis fibroblast-like synoviocytes: possible roles of nitric oxide and the thioredoxin 1

SlTrxh functions downstream of SlMYB86 and positively regulates nitrate stress tolerance via S-nitrosation in tomato seedling

Nitric oxide (NO) is a redox-dependent signaling molecule that plays a crucial role in regulating a wide range of biological processes in plants. It functions by post-translationally modifying proteins, primarily through S-nitrosation. Thioredoxin (Trx), a small and ubiquitous protein with multifunctional properties, plays a pivotal role in the antioxidant defense system. However, the regulatory mechanism governing the response of tomato Trxh (SlTrxh) to excessive nitrate stress remains unknown. In this study, overexpression or silencing of SlTrxh in tomato led to increased or decreased nitrate stress tolerance, respectively. The overexpression of SlTrxh resulted in a reduction in levels of reactive oxygen species (ROS) and an increase in S-nitrosothiol (SNO) contents; conversely, silencing SlTrxh exhibited the opposite trend. The level of S-nitrosated SlTrxh was increased and decreased in SlTrxh overexpression and RNAi plants after nitrate treatment, respectively. SlTrxh was found to be susceptible to S-nitrosation both in vivo and in vitro, with Cysteine 54 potentially being the key site for S-nitrosation. Protein interaction assays revealed that SlTrxh physically interacts with SlGrx9, and this interaction is strengthened by S-nitrosation. Moreover, a combination of yeast one-hybrid (Y1H), electrophoretic mobility shift assay (EMSA), chromatin immunoprecipitation-quantitative PCR (ChIP-qPCR), and transient expression assays confirmed the direct binding of SlMYB86 to the SlTrxh promoter, thereby enhancing its expression. SlMYB86 is located in the nucleus and SlMYB86 overexpressed and knockout tomato lines showed enhanced and decreased nitrate stress tolerance, respectively. Our findings indicate that SlTrxh functions downstream of SlMYB86 and highlight the potential significance of S-nitrosation of SlTrxh in modulating its function under nitrate stress.

Effects of Selenium Supplementation on the Indices of Disease Activity, Inflammation and Oxidative Stress in Patients with Rheumatoid Arthritis: a Randomized Clinical Trial

The aim of study was to evaluate the effect of selenium supplementation on disease activity, inflammation, and oxidative stress in patients with rheumatoid arthritis (RA). This study was a randomized double-blind placebo-controlled trial on 59 patients with RA. Participants were randomly divided to receive 200 μg/day of selenium or a placebo for 12 weeks. The disease activity score (DAS.CRP and DAS.ESR), erythrocyte sedimentation rate (ESR), serum levels of C-reactive protein (CRP), fasting blood glucose, lipids, antibodies to cyclic citrullinated protein (anti-CCP), nitric oxide, glutathione, and total antioxidant capacity were assessed. The mean of DAS.CRP and DAS.ESR decreased significantly within both study groups after the intervention. However, the between-group comparisons revealed no significant differences. The CRP levels decreased significantly in the selenium group, and this decrease was near the significance level compared to the placebo (P = 0.05). However, after adjusting for baseline values, the observed difference between groups did not remain significant. In addition, the values of ESR and anti-CCP decreased significantly within the selenium group. Although, between-group comparison did not statistically significant, the change in ESR and anti-CCP in the selenium group was small clinically relevant compared to the placebo [the effect size (95% CI) for ESR: 0.38 (- 0.14, 0.89), and for anti-CCP: 0.32 (- 0.2, 0.83)]. Our study showed that selenium caused a small clinically relevant improvement in some RA biomarkers such as ESR and anti-CCP. Future studies that evaluate the effects of novel forms of supplements such as selenium nanoparticles on the clinical symptoms and biomarkers of RA are suggested. Trial Registration: At www.irct.ir as IRCT20190924044869N1 on 2020-06-14.

In vitro inhibitory effect of zingerone on TNFα-stimulated fibroblast-like synoviocytes

Targeting Fibroblast-like synoviocytes (FLSs) is an attractive complementary approach for RA therapy. This study aimed to investigate the inhibitory effects of zingerone on TNFα-induced arthritic FLSs. MTS, EdU, wound healing, DHE staining and real-time PCR were used to determine the effects of zingerone on the destructive behaviors of arthritic FLSs induced by TNFα. Western blot analysis was used to analyze cell signaling pathways. Zingerone treatment significantly inhibited TNFα-induced proliferation, migration, ROS formation and pro-inflammatory cytokines expression of FLSs. Molecular mechanism studies revealed that zingerone could suppress TNFα-induced activations of MAPKs (ERK, JNK and p38) in arthritic FLSs. Zingerone attenuated pathological features of FLSs via MAPKs pathways, indicating its potential as a complementary or alternative drug for RA therapy.

The Importance of Thioredoxin-1 in Health and Disease

Thioredoxin-1 (Trx-1) is a multifunctional protein ubiquitously found in the human body. Trx-1 plays an important role in various cellular functions such as maintenance of redox homeostasis, proliferation, and DNA synthesis, but also modulation of transcription factors and control of cell death. Thus, Trx-1 is one of the most important proteins for proper cell and organ function. Therefore, modulation of Trx gene expression or modulation of Trx activity by various mechanisms, including post-translational modifications or protein-protein interactions, could cause a transition from the physiological state of cells and organs to various pathologies such as cancer, and neurodegenerative and cardiovascular diseases. In this review, we not only discuss the current knowledge of Trx in health and disease, but also highlight its potential function as a biomarker.

BAFF Promotes FLS Activation Through BAFFR-Mediated Non-canonical NF-κB Pathway and the Effects of CP-25

B cell activating factor (BAFF) has been shown to play a key role in regulating B cell function, but little is known about whether BAFF affects the function of fibroblast-like synoviocyte (FLS), an effector cell of rheumatoid arthritis (RA). CP-25, a new ester derivative of paeoniflorin, could alleviate the arthritis symptoms of collagen-induced arthritis (CIA) mice by inhibiting BAFF-mediated abnormal activation of B cells. In this study, we aimed to understand the mechanism by which BAFF activates FLS and the effect of CP-25 on FLS function. Therefore, the proliferation and migration abilities of FLS and key proteins on the non-canonical NF-κB pathway were examined. The results showed that compared with the FLS of normal rats/OA patients, the expression of BAFF-R, TRAF2, NIK, p-IKKα, P100, and P52 was higher in the FLS of AA rats/RA patients, while the expression of TRAF3 was lower. And, BAFF promotes FLS activation by activating the non-canonical NF-κB signaling pathway. Meanwhile, BAFFR-siRNA inhibited the proliferation of FLS and the activation of non-canonical NF-κB signaling in FLS induced by BAFF. Additionally, CP-25 could inhibit abnormal proliferation and migration of FLS by regulating non-canonical NF-κB signaling. We concluded that BAFF may act as an important role in facilitating the function of FLS through the BAFFR-mediated non-canonical NF-κB pathway, which would be useful for revealing the pathological mechanism of RA. And CP-25 may become a potential new drug for the treatment of RA, providing a scientific basis for the development of new drugs to treat RA.

Long non-coding RNA MEG3 and its genetic variant rs941576 are associated with rheumatoid arthritis pathogenesis in Egyptian patients

BACKGROUND

Rheumatoid arthritis (RA) is a joint destructive disorder. This study aimed to assess lncRNA MEG3 expression and its variant rs941576 in Egyptian patients with RA.

SUBJECTS AND METHODS

100 RA patients and 100 healthy individuals were enrolled in the study. Quantitative PCR was used for expression analysis and allelic discrimination technology for genotyping.

RESULTS

LncRNA MEG3 was down-regulated in RA patients and negatively associated with RA clinical features and HIF-1α and VEGF serum levels. On the contrary, it was positively associated with BAX serum levels in RA patients. The major A allele of rs941576 variant was associated with RA patients (p = .0003). AA genotype showed a significant decrease in lncRNA MEG3 expression and BAX and increase in HIF-1α and VEGF.

CONCLUSIONS

Serum lncRNA MEG3 expression showed negative association with increased susceptibility to RA. MEG3 gene rs941576 (A/G) polymorphism was associated with increased severity of RA in the current population.

Epimedii Herba: An ancient Chinese herbal medicine in the prevention and treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, progressive inflammatory and systemic autoimmune disease resulting in severe joint destruction, lifelong suffering and considerable disability. Diverse prescriptions of traditional Chinese medicine (TCM) containing Epimedii Herba (EH) achieve greatly curative effects against RA. The present review aims to systemically summarize the therapeutic effect, pharmacological mechanism, bioavailability and safety assessment of EH to provide a novel insight for subsequent studies. The search terms included were "Epimedii Herba", "yinyanghuo", "arthritis, rheumatoid" and "Rheumatoid Arthritis", and relevant literatures were collected on the database such as Google Scholar, Pubmed, Web of Science and CNKI. In this review, 15 compounds from EH for the treatment of RA were summarized from the aspects of anti-inflammatory, immunoregulatory, cartilage and bone protective, antiangiogenic and antioxidant activities. Although EH has been frequently used to treat RA in clinical practice, studies on mechanisms of these activities are still scarce. Various compounds of EH have the multifunctional traits in the treatment of RA, so EH may be a great complementary medicine option and it is necessary to pay more attention to further research and development.

Effects of electroconvulsive therapy on nitrosative stress and oxidative DNA damage parameters in patients with a depressive episode

BACKGROUND

Few studies have investigated the relationship between electroconvulsive therapy (ECT) and markers of nitrosative stress and oxidative DNA damage.

OBJECTIVE

The aim of this study is to examine changes in nitrosative stress and oxidative DNA damage in patients with a depressive episode treated with ECT.

METHODS

The current study included 48 patients with a depressive episode treated with ECT and 30 healthy control participants. First, the serum nitrosative stress markers of nitric oxide (NO•), nitric oxide synthase (NOS), and peroxynitrite (ONOO-) and the oxidative DNA damage marker 8-hydroxy-2'-deoxyguanosine (8-OHdG) were compared between the study and control groups. These parameters were also compared pre- and post-treatment for the study group.

RESULTS

NO•, NOS, and ONOO- levels were significantly higher in patients with depressive disorder (DD) than in the control group. NO• and NOS levels significantly decreased in the ECT group after treatment while 8-OHdG levels significantly increased.

CONCLUSIONS

The study findings suggest that ECT may have reduced nitrosative stress levels while increasing oxidative DNA damage. More research is now needed to better understand the issue.KEY POINTSNitrosative stress levels can increase in patients with depressive disorder.Electroconvulsive therapy may reduce nitrosative stress while increasıng oxidative DNA damage.These results suggest that nitrosative stress plays an important role in the mechanism of action of electroconvulsive therapy.

Investigation of the mechanism of Isobavachalcone in treating rheumatoid arthritis through a combination strategy of network pharmacology and experimental verification

ETHNOPHARMACOLOGY RELEVANCE

Isobavachalcone (IBC) is a natural chalcone compound widely distributed in traditional Chinese medicine Psoralea corylifolia L., and Tibetan medicine Abelmoschus manihot (L.) Medik. Etc.. Among them, Psoralea corylifolia has the effect of tonifying the kidney and strengthening Yang, and it is recorded in the Medicinal theory that it can be used in managing rheumatism and arthralgia. In addition, It has been included in many prescriptions in traditional Chinese medicine as the main herb for managing rheumatoid arthritis (RA). Similarly, Abelmoschus manihot is a common Tibetan medicinal herb and is a common medicinal material in Tibetan medicine and reported in ancient medicinal books such as Jing Zhu Ben Cao and Si Bu Yi Dian to possess the effect of Ganhuangshui and thus can be used in treating Huangshui diseases (such as RA). Previous research has demonstrated IBC to possess numerous biological activities, including anti-cancer, anti-inflammatory, antibacterial and immunomodulatory. Nevertheless, its efficacy and potential mechanism in treating rheumatoid arthritis are yet to be investigated.

AIM OF THE STUDY

This study aimed at investigating the therapeutic efficacy and mechanism of IBC in treating RA through a combined strategy of network pharmacology, in vitro, and in vivo evaluation.

MATERIALS AND METHODS

The Swiss Target Prediction and GeneCards databases were consulted to predict the potential targets of IBC and RA. Additionally, the potential targets for IBC in treating RA were predicted by consulting databases such as String, Cytoscape, MCODE, and Cytohubba. R software was utilized for enrichment analysis of GO and KEGG pathways, followed by in vitro experimentation using cell lines and in vivo experimentation using animals to explore the potential mechanism of IBC in RA treatment.

RESULTS

By integrating the results of network pharmacological analysis, 17 genes were found to be strongly associated with RA, such as TNF, MAPK13, EGFR, PTGS2, MMP3, etc. The enrichment analysis indicated that IBC possessed tremendous therapeutic efficacy in managing RA through PI3K-AKT, rheumatoid arthritis, and TNF signaling pathways. The in vitro experimentation indicated that IBC inhibited the proliferation, migration, and invasion, and promoted apoptosis and inhibition of inflammation of MH7A cell lines stimulated with TNF-α. The IBC might also have an increasing effect on the intracellular ROS and reducing effect on the mitochondrial membrane potential. The western blotting results indicated that IBC markedly inhibited the expression of p-PI3K, p-AKT, p-JAK1, p-STAT3 and SOCS3 proteins in TNF-α stimulated MH7A cells. Furthermore, we found that IBC also significantly reduced paw swelling and arthritis severity in CIA model rats through in vivo animal studies.

CONCLUSIONS

In short, this study explored the effect of IBC by combining network pharmacology prediction with in vitro and in vivo experimentation. The results indicated that IBC exerts its anti-rheumatoid arthritis effect by regulating cell proliferation and survival via PI3K/AKT and JAK/STAT signaling pathways. This may open a new horizon and provide a theoretical foundation for further development and utilization of IBC in RA management.

YWHAH Genetic Variants are Associated with Increased Hypoxia Inducible Factor-1α/Vascular Endothelial Growth Factor in Egyptian Rheumatoid Arthritis Patients

The 14-3-3 Eta (14-3-3 η) biomarker platform is a relatively recent discovery with the potential to significantly address the diagnosis and prognosis of rheumatoid arthritis (RA) disease. Hypoxia-inducible factor (HIF)-1α and vascular endothelial growth factor (VEGF) have been implicated in inflammatory mechanisms in RA. We hypothesized a molecular association of the coding YWHAH gene and its expressed protein 14-3-3 η with hypoxia and angiogenesis in RA. One hundred healthy subjects and 100 RA patients were enrolled in the study. YWHAH gene expression was determined using quantitative PCR, and its gene polymorphism rs2858750 was assessed by Taqman genotyping assay. Serum levels of 14-3-3 η, HIF-1α, and VEGF were measured using the ELISA technique, and clinical parameters were routinely examined. In RA patients, significant positive correlations were found between 14-3-3 η, HIF-1α (r = 0.84), and VEGF (r = 0.85). YWHAH gene expression was upregulated 10.8 fold (CI 95% 10.1-11.5) in RA patients and significantly correlated with all disease activity parameters, ACPA, and levels of 14-3-3 η, HIF-1α, and VEGF. RA patients showed a higher frequency of YWHAH rs2858750 A allele than healthy subjects (p = 0.02). The risk A allele carriers showed higher disease activity parameters, ACPA, YWHAH gene expression, and increased serum levels of 14-3-3 η (p < 0.001), HIF-1α (p = 0.002), and VEGF (p = 0.001) than the G allele. Serum 14-3-3 η and its rs2858750 genetic variant are associated with increased hypoxia and angiogenesis in RA and activity, and severity of the disease.

The Role of Cell Organelles in Rheumatoid Arthritis with Focus on Exosomes

Auto-immune diseases involved at least 25% of the population in wealthy countries. Several factors including genetic, epigenetic, and environmental elements are implicated in development of Rheumatoid Arthritis as an autoimmune disease. Autoantibodies cause synovial inflammation and arthritis, if left untreated or being under continual external stimulation, could result in chronic inflammation, joint injury, and disability. T- and B-cells, signaling molecules, proinflammatory mediators, and synovium-specific targets are among the new therapeutic targets. Exosomes could be employed as therapeutic vectors in the treatment of autoimmune diseases. Herein, the role of cell organelle particularly exosomes in Rheumatoid Arthritis had discussed and some therapeutic applications of exosome highlighted.

Kruppel-like factor 4 upregulates the resistance to apoptosis induced by tumor necrosis factor α in synovial fibroblasts with rheumatoid arthritis

Objective

The objective is to examine the effect of tumor necrosis factor α (TNFα) on apoptosis and proliferation of rheumatoid arthritis synovial fibroblasts (RASFs) and to elucidate the regulatory roles of Kruppel-like factor 4 (KLF4) in TNFα-induced RASF apoptosis.

Methods

Changes in cell proliferation were measured using an 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di- phenytetrazoliumromide (MTT) assay, and changes in cell apoptosis were detected by flow cytometry and Hoechst 33258 staining. Changes in the apoptosis-related protein caspase-3 and the apoptosis-related genes bcl-2/bax were measured by western blot and real-time PCR, respectively

Results

TNFα stimulation increased cell proliferation ( p < 0.05), decreased cell apoptosis ( p < 0.05), declined caspase-3 expression ( p < 0.05), and upregulated bcl-2/bax level ( p < 0.05) in RASFs. KLF4 gene silencing decreased cell proliferation ( p < 0.05), increased cell apoptosis ( p < 0.05), upregulated caspase-3 expression ( p < 0.05), and downregulated bcl-2/bax level ( p < 0.05) induced by TNFα in RASFs.

Conclusions

TNFα caused a decrease in RASF apoptosis, and KLF4 promoted resistance to TNFα-induced apoptosis and cell proliferation.

The p53 status in rheumatoid arthritis with focus on fibroblast-like synoviocytes

P53 is a transcription factor that regulates many signaling pathways like apoptosis, cell cycle, DNA repair, and cellular stress responses. P53 is involved in inflammatory responses through the regulation of inflammatory signaling pathways, induction of cytokines, and matrix metalloproteinase expression. Also, p53 regulates immune responses through modulating Toll-like receptors expression and innate and adaptive immune cell differentiation and maturation. P53 is a modulator of the apoptosis and proliferation processes through regulating multiple anti and pro-apoptotic genes. Rheumatoid arthritis (RA) is categorized as an invasive inflammatory autoimmune disease with irreversible deformity of joints and bone resorption. Different immune and non-immune cells contribute to RA pathogenesis. Fibroblast-like synoviocytes (FLSs) have been recently introduced as a key player in the pathogenesis of RA. These cells in RA synovium produce inflammatory cytokines and matrix metalloproteinases which results in synovitis and joint destruction. Besides, hyper proliferation and apoptosis resistance of FLSs lead to synovial hyperplasia and bone and cartilage destruction. Given the critical role of p53 in inflammation, apoptosis, and cell proliferation, lack of p53 function (due to mutation or low expression) exerts a prominent role for this gene in the pathogenesis of RA. This review focuses on the role of p53 in different mechanisms and cells (specially FLSs) that involved in RA pathogenesis.

Integrated nanomaterials for non-invasive photothermal therapy of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic systemic inflammatory autoimmune disease that causes swelling, redness, and arthralgia of multiple joints. Despite significant research and development on the treatment modalities for RA, there is still no established effective treatment option for eradicating joint damage and inflammation. In recent years, photothermal therapy (PTT) has emerged as a practical approach to treat RA. In this review, we outline various factors that affect the effective treatment of RA. Moreover, we discuss various PTT-based nanomaterials that can be used to treat RA.

Kaempferia parviflora Extract Alleviated Rat Arthritis, Exerted Chondroprotective Properties In Vitro, and Reduced Expression of Genes Associated with Inflammatory Arthritis

Kaempferia parviflora Wall. ex Baker (KP) has been reported to attenuate cartilage destruction in rat model of osteoarthritis. Previously, we demonstrated that KP rhizome extract and its active components effectively suppressed mechanisms associated with RA in SW982 cells. Here, we further evaluated the anti-arthritis potential of KP extract by using multi-level models, including a complete Freund’s adjuvant-induced arthritis and a cartilage explant culture model, and to investigate the effects of KP extract and its major components on related gene expressions and underlying mechanisms within cells. In arthritis rats, the KP extract reduced arthritis indexes, with no significant changes in biological parameters. In the cartilage explant model, the KP extract exerted chondroprotective potential by suppressing sulfated glycosaminoglycans release while preserving high accumulation of proteoglycans. In human chondrocyte cell line, a mixture of the major components equal to their amounts in KP extract showed strong suppression the expression of genes-associated inflammatory joint disease similar to that of the extract. Additionally, KP extract significantly suppressed NF-κB and MAPK signaling pathways. The suppressing expression of necroptosis genes and promoted anti-apoptosis were also found. Collectively, these results provided supportive evidence of the anti-arthritis properties of KP extract, which are associated with its three major components.

Anti-proliferation and anti-migration effects of an aqueous extract of Cinnamomi ramulus on MH7A rheumatoid arthritis-derived fibroblast-like synoviocytes through induction of apoptosis, cell arrest and suppression of matrix metalloproteinase

CONTEXT

Cinnamomi ramulus, the dry twig of Cinnamomum cassia Presl. (Lauraceae), has been reported to exert several activities such as antitumor, anti-inflammatory, and analgesic effects.

OBJECTIVE

This study investigates the effects of an aqueous extract of Cinnamomi ramulus (ACR) on rheumatoid arthritis (RA).

MATERIALS AND METHODS

TNF-α-induced RA-derived fibroblast-like synoviocyte MH7A cells were incubated with ACR (0.1-2 mg/mL) for 24 h. The proliferation was tested using CCK-8 and colony formation assays. The migration and invasion abilities were measured using transwell tests and wound healing assays. Apoptosis and cell cycle were examined by flow cytometry. The potential mechanisms were determined by western blotting and quantitative real-time PCR. UPLC-QE-MS/MS was used for chromatographic analysis of ACR and its compounds were identified. Molecular docking strategy was used to screen the potential anti-RA active compounds of ACR.

RESULTS

We found that ACR induced apoptosis in MH7A cells at concentrations of 0.4, 0.8, and 1.2 mg/mL. The proliferation of MH7A cells was reduced and the cell cycle was blocked in the G2/M phase at concentrations of 0.2, 0.4, 0.6 mg/mL. Migration and invasion of MH7A cells were reduced through inhibiting the expression of MMP-1, MMP-2, and MMP-3. The molecular docking strategy results showed that 9 compounds in ACR have good affinity with protein crystal, and benzyl cinnamate (10-100 µg/mL) could inhibit cell migration and induce apoptosis.

CONCLUSIONS

The anti-RA effect of ACR may be attributed to its anti-proliferative and anti-migration effects on synovial fibroblasts. These data suggest that Cinnamomi ramulus may have therapeutic value for the treatment of RA.

Identification of putative master regulators in rheumatoid arthritis synovial fibroblasts using gene expression data and network inference

Rheumatoid arthritis (RA) is a systemic autoimmune disease that affects the synovial joints of the body. Rheumatoid arthritis fibroblast-like synoviocytes (RA FLS) are central players in the disease pathogenesis, as they are involved in the secretion of cytokines and proteolytic enzymes, exhibit invasive traits, high rate of self-proliferation and an apoptosis-resistant phenotype. We aim at characterizing transcription factors (TFs) that are master regulators in RA FLS and could potentially explain phenotypic traits. We make use of differentially expressed genes in synovial tissue from patients suffering from RA and osteoarthritis (OA) to infer a TF co-regulatory network, using dedicated software. The co-regulatory network serves as a reference to analyze microarray and single-cell RNA-seq data from isolated RA FLS. We identified five master regulators specific to RA FLS, namely BATF, POU2AF1, STAT1, LEF1 and IRF4. TF activity of the identified master regulators was also estimated with the use of two additional, independent software. The identified TFs contribute to the regulation of inflammation, proliferation and apoptosis, as indicated by the comparison of their differentially expressed target genes with hallmark molecular signatures derived from the Molecular Signatures Database (MSigDB). Our results show that TFs influence could be used to identify putative master regulators of phenotypic traits and suggest novel, druggable targets for experimental validation.

Adalimumab changes the expression profile of selected BCL-2 family genes

Biological drugs are an alternative to treatment of psoriasis and psoriatic arthritis. Adalimumab is a representative of the anti-TNF group. The underlying of this disease is a cellular homeostasis disorder-apoptosis. Many proteins are involved in the apoptosis induction pathways, including those from the BCL-2 family. The aim of the study was to perform a transcriptional analysis of the genes coding selected proteins from the BCL-2 family in patients treated with adalimumab therapy, and to determine the direction of these changes. The test materials were peripheral blood mononuclear cells. The cells were obtained from 20 patients with psoriatic arthritis who were being treated with adalimumab (study group) and 20 healthy volunteers (control). The gene expression profile was determined using the real-time quantitative reverse transcription polymerase chain reaction technique. Statistically significant changes were observed in the expression level of the BNIP3, BNIP3L, and BCL2L1 genes (p < .05) during a 24-month observation of therapy. We indicated that adalimumab therapy has an impact on the expression of the analyzed genes, which may constitute a new class of molecular markers for assessing the effectiveness of a therapy. It appears that the BNIP3L gene could be used as a potential diagnostic marker of psoriasis.

Comparative study of HO-1 expressing synovial lining cells between RA and OA

OBJECTIVES

We aimed to clarify the characteristics of heme oxygenase (HO)-1 expressing cells in the synovium from rheumatoid arthritis (RA) and osteoarthritis (OA), and to investigate the co-expression of HO-1 and IgG-Fc/HLA-DR complex.

METHODS

The characteristics of HO-1 expressing cells in the synovium were investigated by using immunohistochemistry. The co-expression of HO-1 and IgG-Fc/HLA-DR complex was examined by an in situ proximity ligation assay (PLA) with immunofluorescence. HO-1 mRNA was investigated by reverse transcription-polymerase chain reaction.

RESULTS

The number of HO-1⁺ cells from the RA synovium is higher than that from OA synovium. The double positive cells of HO-1 and IgG-Fc/HLA-DR complex were detected by the in situ PLA with immunofluorescence in RA synovium. HO-1 mRNA was detected in both RA and OA synovium.

CONCLUSION

A portion of HO-1⁺ cells with IgG-Fc/HLA-DR complex in lining layer of RA may be concluded as one of antigen presenting cells in RA and may be involved in production of RF.

The promoting effect of MMP13 on mediating the development of HFLS-RA by the target of miR-19a through IL-17 signaling pathway

By investigating the expression profiles of miR-19a and metalloproteinases (MMP13) in human fibroblast-like synoviocytes-rheumatoid arthritis (HFLS-RA) and HFL cells lines, this study intends to confirm the directly target connection between them and reveal the effect of suppressing MMP13 on HLFS-RA migration, invasion and apoptosis. After screening the abnormal expressed messenger RNAs and microRNAs in synovial tissues of patients with RA, the underlying pathway was determined by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. The HFLS-RA cell line was transfected for the following experiments with pcDNA3.1(+) served as vector. The directly target association between miR-19a and MMP13 was confirmed by Luciferase reporter assay. Microarray analysis suggested that MMP13 was upregulated while miR-19a was downregulated in HFLS of RA tissues compared with the healthy control group. MMP13 was related to many proteins in protein-protein interaction network, which might be the main influencing factor of RA. KEGG pathway analysis identified that interleukin (IL)-17 pathway was activated in the regulation of MMP13 in the development of RA. Through observing the alteration of luciferase activity, miR-19a could indeed bind to the 3'UTR of the downstream of MMP13, the target association was then confirmed. The proliferation and invasion of HFLS-RA were promoted by overexpressing MMP13 protein. miR-19a could function as a suppressor of MMP13 and thereby retard the severity of RA. The results showed that miR-19a could regulate the expression of MMP13 in HFLS-RA by mediating the proliferation and invasion of HFLS-RA through IL-17 signaling pathway, thereby participating in the degradation of chondrocytes in the progression of RA.

RA-map: building a state-of-the-art interactive knowledge base for rheumatoid arthritis

Rheumatoid arthritis (RA) is a progressive, inflammatory autoimmune disease of unknown aetiology. The complex mechanism of aetiopathogenesis, progress and chronicity of the disease involves genetic, epigenetic and environmental factors. To understand the molecular mechanisms underlying disease phenotypes, one has to place implicated factors in their functional context. However, integration and organization of such data in a systematic manner remains a challenging task. Molecular maps are widely used in biology to provide a useful and intuitive way of depicting a variety of biological processes and disease mechanisms. Recent large-scale collaborative efforts such as the Disease Maps Project demonstrate the utility of such maps as versatile tools to organize and formalize disease-specific knowledge in a comprehensive way, both human and machine-readable. We present a systematic effort to construct a fully annotated, expert validated, state-of-the-art knowledge base for RA in the form of a molecular map. The RA map illustrates molecular and signalling pathways implicated in the disease. Signal transduction is depicted from receptors to the nucleus using the Systems Biology Graphical Notation (SBGN) standard representation. High-quality manual curation, use of only human-specific studies and focus on small-scale experiments aim to limit false positives in the map. The state-of-the-art molecular map for RA, using information from 353 peer-reviewed scientific publications, comprises 506 species, 446 reactions and 8 phenotypes. The species in the map are classified to 303 proteins, 61 complexes, 106 genes, 106 RNA entities, 2 ions and 7 simple molecules. The RA map is available online at ramap.elixir-luxembourg.org as an open-access knowledge base allowing for easy navigation and search of molecular pathways implicated in the disease. Furthermore, the RA map can serve as a template for omics data visualization.

Mitochondrial dysfunction in rheumatoid arthritis: A comprehensive analysis by integrating gene expression, protein-protein interactions and gene ontology data

Several studies have reported mitochondrial dysfunction in rheumatoid arthritis (RA). Many nuclear DNA (nDNA) encoded proteins translocate to mitochondria, but their participation in the dysfunction of this cell organelle during RA is quite unclear. In this study, we have carried out an integrative analysis of gene expression, protein-protein interactions (PPI) and gene ontology data. The analysis has identified potential implications of the nDNA encoded proteins in RA mitochondrial dysfunction. Firstly, by analysing six synovial microarray datasets of RA patients and healthy controls obtained from the gene expression omnibus (GEO) database, we found differentially expressed nDNA genes that encode mitochondrial proteins. We uncovered some of the roles of these genes in RA mitochondrial dysfunction using literature search and gene ontology analysis. Secondly, by employing gene co-expression from microarrays and collating reliable PPI from seven databases, we created the first mitochondrial PPI network that is specific to the RA synovial joint tissue. Further, we identified hubs of this network, and moreover, by integrating gene expression and network analysis, we found differentially expressed neighbours of the hub proteins. The results demonstrate that nDNA encoded proteins are (i) crucial for the elevation of mitochondrial reactive oxygen species (ROS) and (ii) involved in membrane potential, transport processes, metabolism and intrinsic apoptosis during RA. Additionally, we proposed a model relating to mitochondrial dysfunction and inflammation in the disease. Our analysis presents a novel perspective on the roles of nDNA encoded proteins in mitochondrial dysfunction, especially in apoptosis, oxidative stress-related processes and their relation to inflammation in RA. These findings provide a plethora of information for further research.

Syndecan-4 involves in the pathogenesis of rheumatoid arthritis by regulating the inflammatory response and apoptosis of fibroblast-like synoviocytes

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease, and the pathogenesis of RA is still unknown. Rheumatoid arthritis fibroblast-like synoviocytes (RA-FLSs) are of significance in the pathogenesis of RA. In this study, three microarray profiles (GSE55457, GSE55584, and GSE55235) of human joint FLSs from 33 RA patients and 20 normal controls were extracted from the Gene Expression Omnibus Dataset and analyzed to investigate the underlying pathogenesis of RA. As analyzed by the differently expressed genes, gene ontology, Kyoto Encyclopedia of Genes and Genomes pathway enrichment, and protein-protein interaction network analysis, syndecan-4 (SDC4), a receptor of multiple cytokines and chemokines, which played a key role in the regulation of inflammatory response, was found to be an essential regulator in RA. To further validate these results, the levels of SDC4, reactive oxygen species (ROS), nitric oxide (NO), inflammation, and apoptosis in RA-FLSs were examined. SDC4-silenced RA-FLSs were also used. The results demonstrated that SDC4 and the level of ROS, NO, and inflammation were highly expressed while the apoptosis was decreased in RA-FLSs compared with normal FLSs. SDC4 silencing significantly suppressed the levels of ROS, NO, and inflammation; elevated the expression of nuclear factor erythroid 2-related factor 2; and promoted the apoptosis of RA-FLSs. Collectively, our results demonstrated a new mechanism of SDC4 in initiating the inflammation and inhibiting the apoptosis of RA-FLSs and that a potential target for the diagnosis and treatment of RA in the clinic might be developed.

miR-449a inhibits cell proliferation, migration, and inflammation by regulating high-mobility group box protein 1 and forms a mutual inhibition loop with Yin Yang 1 in rheumatoid arthritis fibroblast-like synoviocytes

Background

We previously found that high-mobility group box protein 1 (HMGB1) promoted cell proliferation, migration, invasion, and autophagy in rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS), but little is known about its regulatory mechanism. The aim of this study was to investigate the regulatory mechanism of HMGB1 at the posttranscription level.

Methods

Real-time qPCR, CCK-8 cell proliferation assay, transwell cell migration assay, enzyme-linked immunosorbent assay (ELISA), and western blotting were used in this study. The targeting relationship between miRNA and mRNA was presented by the luciferase reporter assay.

Results

MiR-449a was downregulated in RA synovial tissue and inhibited RA-FLS proliferation, migration, and IL-6 production. MiR-449a directly targeted HMGB1 and inhibited its expression. Yin Yang 1(YY1) negatively regulated miR-449a expression and formed a mutual inhibition loop in RA-FLS. MiR-449a inhibited TNFα-mediated HMGB1 and YY1 overexpression and IL-6 production.

Conclusions

Our results reveal the regulatory mechanism of HMGB1 in RA and demonstrate that miR-449a is a crucial molecule in RA pathogenesis and a suitable candidate for miRNA replacement therapies in RA.

Electronic supplementary material

The online version of this article (10.1186/s13075-019-1920-0) contains supplementary material, which is available to authorized users.

Liquiritin from Glycyrrhiza uralensis Attenuating Rheumatoid Arthritis via Reducing Inflammation, Suppressing Angiogenesis, and Inhibiting MAPK Signaling Pathway

Among the various treatments, induction of synoviocyte apoptosis by natural products during a rheumatoid arthritis (RA) pathological condition can be considered to have vast potential. However, it is unclear that liquiritin, a kind of natural flavonoid extracted from the roots of Glycyrrhiza uralensis, induced the apoptosis of the synovial membrane and its molecular mechanism. In this study, interleukin-1β (IL-1β)-RA-FLS cells were incubated with different concentrations of liquiritin. An MTT assay, Hoechst 33342 staining, JC-1 staining, and Western blot were used to check the viability, cell apoptosis, mitochondrial membrane potential changes, and the expression of related proteins, respectively. In vivo, a TUNEL assay and HE staining of tissue were used for histopathological evaluation. Our results showed that liquiritin significantly inhibited the proliferation of IL-1β-induced-RA-FLS, promoted nuclear DNA fragmentation, and changed the mitochondrial membrane potential to accelerate cell apoptosis. Liquiritin downregulated the ratio of Bcl-2/Bax and inhibited the VEGF expression and phosphorylation of JNK and P38. Moreover, liquiritin improved the clinical score of rheumatism, inflammatory infiltration, and angiogenesis and induced apoptosis of the synovial tissue in vivo. Hence, liquiritin ameliorates RA by reducing inflammation, blocking MAPK signaling, and restraining angiogenesis.

Involvement of miR-126 in autoimmune disorders

BACKGROUND

Micro-RNA represent a great family of small non-condign ribonucleic acid molecules; in particular microRNA-126 is an important member of this family and is expressed in many human cells such as cardiomyocytes, endothelial and lung cells. Some studies have shown the implication of miR-126 in cancer, but recently significant progresses have also been made in determining the role of miR-126 regulating immune-related diseases; probably, in a near future, they could potentially serve as diagnostic biomarkers or therapeutic targets.

OBJECTIVE

The purpose of this review is to investigate the role of miR-126 in autoimmune diseases, so as to offer innovative therapies.

RESULTS

According literature, it was concluded that miRNAs, especially miR-126, are involved in many pathologies and that their expression levels increase in autoimmune diseases because they interfere with the transcription of the proteins involved. Since microRNAs can be detected from several biological sources, they may be attractive as potential biomarkers for the diagnosis, prognosis, disease activity and severity of various diseases. In fact, once confirmed the involvement of miR-126 in autoimmune diseases, it was speculated that it could be used as a promising biomarker. These discovers implicate that miR-126 have a central role in many pathways leading to the development and sustain of autoimmune diseases. Its key role make this microRNA a potential therapeutic target in autoimmunity.

CONCLUSION

Although miR-126 relevant role in several immune-related diseases, further studies are needed to clear its molecular mechanisms; the final step of these novel researches could be the blockage or the prevention of the diseases onset by creating of new targeted therapy.

Down-regulation of miR-10a-5p promotes proliferation and restricts apoptosis via targeting T-box transcription factor 5 in inflamed synoviocytes

Synoviocytes from rheumatoid arthritis (RA) patients share certain features with tumor cells, such as over proliferation and invasion. Anomalous microRNA (miRNA) expression may participate in the pathogenesis of RA in different ways. The objective of the present study was to observe the role of miR-10a-5p targeting T-box transcription factor 5 (TBX5) gene on synoviocyte proliferation and apoptosis in RA. Human synovial sarcoma cell line, SW982 cells stimulating with interleukin-1β (IL-1β) were transfected with miR-10a-5p mimic and siRNA of TBX5. The real-time quantitative polymerase chain reaction (RT-qPCR) and Western blotting analysis were used to evaluate the expression level of miR-10a-5p and TBX5 in SW982 cells respectively. Further, the proliferation and apoptosis of SW982 cells after treatment were determined by cell counting kit (CCK-8) and flow cytometry analysis respectively. We found that the miR-10a-5p showed down-regulated while TBX5 showed up-regulated expression in synoviocytes after stimulation with IL-1β. The miR-10a-5p mimic treatment showed a decline in cell proliferation while the increased rate of cell apoptosis as compared with control. Moreover, knockdown of TBX5 favored the apoptosis and reduced the cell proliferation as compared with control group. We conclude that down-regulation of miR-10a-5p promotes proliferation and restricts apoptosis via targeting TBX5 in inflamed synoviocytes.

Effects of lentivirus-mediated ornithine decarboxylase gene on the proliferation and apoptosis of fibroblast-like synoviocytes in rats with arthritis

OBJECTIVE

This study aimed to explore the effects of lentivirus-mediated ornithine decarboxylase (ODC) gene on the proliferation and apoptosis of fibroblast-like synoviocytes (FLSs) in rats with rheumatoid arthritis (RA).

METHODS

Twenty Lewis rats were randomized into control group (ten rats without processing) and RA group (ten rats of adjuvant-induced arthritis). The third-generation FLSs were randomized into test, control and blank groups. MTT assay and flow cytometry were employed to detect cell proliferation and apoptosis, respectively. Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of tumor necrosis factor α (TNF-α), interferon-γ (IFN-γ), and interleukin-2 (IL-2).

RESULTS

Lewis rats in the RA group became ill from 11days on and got seriously ill 18days after modeling. However, rats in the control group had no obvious change. MTT assay showed that the test group had higher cell proliferation than the blank and control groups (P₁<0.001; P₂<0.001). Flow cytometry revealed that the apoptosis of FLSs in the test group was significantly lower than that in the blank and control groups (P₁<0.001; P₂<0.001). ELISA showed that the test group had higher TNF-α, IFN-γ and IL-2 level than the control and blank groups (all P<0.001), but no significant difference was found between the control and blank groups (all P>0.05).

CONCLUSION

The results indicated that overexpression of ODC gene promotes the proliferation while suppressing apoptosis of FLSs in rats with RA.

Hypoxia‑induced autophagy is inhibited by PADI4 knockdown, which promotes apoptosis of fibroblast‑like synoviocytes in rheumatoid arthritis

Impaired apoptosis of rheumatoid arthritis (RA)-fibroblast-like synoviocytes (FLS) is pivotal in the process of RA. Peptidyl arginine deiminase type IV (PADI4) is associated with autoantibody regulation via histone citrullination in RA. The present study aimed to investigate the role of PADI4 in the apoptosis of RA-FLS. FLS were isolated from patients with RA and a rat model. The effects of PADI4 on RA-FLS were investigated in vitro and in vivo. Hypoxia-induced autophagy was induced by 1% O₂ and was detected by immunohistochemical and immunofluorescence analysis; in addition, apoptosis was detected by flow cytometry. RA-FLS obtained from RA rat model exhibited significant proliferation under severe hypoxia conditions. Hypoxia also significantly induced autophagy and elevated the expression of PADI4. Subsequently, short hairpin RNA-mediated PADI4 knockdown was demonstrated to significantly inhibit hypoxia-induced autophagy and promote apoptosis in RA-FLS. The results of these in vitro and in vivo studies suggested that PADI4 may be closely associated with hypoxia-induced autophagy, and the inhibition of hypoxia-induced autophagy by PADI4 knockdown may contribute to an increase in the apoptosis of RA-FLS.

Death effects of reveromycin A in normal and disease-associated cells of the joint

Earlier work in our laboratory demonstrated that naturally occurring reveromycin A (Rev A) causes apoptosis in osteoclasts without accompanying necrosis. Rev A death effects in both normal and diseased joint cells were investigated in this study. A dose of 10 μM Rev A did not cause apoptosis nor necrosis in monolayer chondrocytes, even at pH 6.8, a pH mimicking that of an inflamed joint. In contrast, at the acidic pH Rev A did induce significant apoptosis (fourfold increase at 48 h of treatment, P < 0.005) in normal synoviocytes without accompanying necrosis. Western blot of the normal synoviocyte proteins revealed that cytochrome c levels were not significantly changed over the time course of treatment nor did caspase 8 activity increase; therefore, Rev A appears to exert this apoptotic effect through a mechanism independent of the classical intrinsic and extrinsic pathways. Fibroblast-like synoviocytes isolated from rheumatoid arthritis patients (RAFLS) as well as normal human fibroblast-like synoviocytes (NHFLS), cells known to play key roles in arthritic joint pathology, were also subjected to Rev A treatment at both physiologic and acidic pH's. Neither apoptosis nor necrosis was induced in either RAFLS or NHFLS. Parallel mitomycin C treatment of NHFLS induced both apoptosis and necrosis. Comparative structure-activity analyses of Rev A and mitomycin C revealed that Rev A is less likely to cross the cell membrane at near neutral pH. Collectively the data reveal that a physiological dose of Rev A under acidic conditions induces normal synoviocytes to undergo apoptosis while pathologic fibroblast-like synoviocytes are resistant to apoptosis and necrosis.

Functional research and molecular mechanism of Kainic acid-induced denitrosylation of thioredoxin-1 in rat hippocampus

Thioredoxin-1 (Trx1) has long been recognized as a redox regulator, and is implicated in the inhibition of cell apoptosis. Trx1 is essential for the maintenance of the S-nitrosylation of molecules in cells. The S-nitrosylation of Trx1 is essential for the physiological function such as preservation of the redox regulatory activity. The mechanisms underlying Trx1 denitrosylation induced by kainate acid (KA) injection still remain uncharacterized. Our results showed that the S-nitrosylation levels of Trx1 were decreased subsequent to KA injection and that the glutamate receptor 6 (GluR6) antagonist NS102 could inhibit the denitrosylation of Trx1. Moreover, the denitrosylation of Trx1 following KA treatment could be suppressed by the Fas ligand (FasL) antisense oligodeoxynucleotides (AS-ODNs), the Trx reductase (TrxR) inhibitor dinitrochlorobenzene (DNCB), or the Nitric oxide (NO) donors sodium nitroprusside (SNP) and S-nitrosoglutathione (GSNO). Subsequently, these mechanisms were morphologically validated by cresyl violet staining, in situ TUNEL staining to detect the survival of CA1 and CA3/DG pyramidal neurons. NS102, FasL AS-ODNs, GSNO and SNP could provide neuroprotection of the pyramidal neurons of CA1 and CA3/dentate gyrus (DG) regions by attenuating Trx1 denitrosylation. Our results also showed that the denitrosylation of Trx1 induced by KA injection can active the caspase-3 which results in apoptosis.

Increased autophagy in fibroblast-like synoviocytes leads to immune enhancement potential in rheumatoid arthritis

The incidence of rheumatoid arthritis (RA) has been reported to be correlated with a disorder of immunregulation. Rheumatoid arthritis fibroblast-like synoviocytes (RA-FLSs) play an important role in regulating the local immune microenvironment. However, the potential mechanism of RA-FLS in regulating the immnue response is not clearly understood. In this study, we demonstrated that the expression of HIF-1α was significantly up-regulated in rheumatoid arthritis tissue which indicated that the hypoxia condition in the microenvironment. We also observed that RA-FLSs demonstrated the potential to up-regulate immune activation. Meanwhile, the level of autophagy increased in RA-FLSs compared with control group. Besides that, the expression of IL-6 was up-regulated not only in RA-FLSs but also in the fibroblasts that treated with hypoxia condition. Accordingly, we found that autophagy inhibitiors could effectively inhibit the immune activation function of RA-FLSs medicated by IL-6. Taken together, the results we demonstrated above indicated that the hypoxia microenvironment could effectively induce the incidence of autophagy and then lead to the immune activation function of RA-FLSs medicated by IL-6.

Immunobiology of Nitric Oxide and Regulation of Inducible Nitric Oxide Synthase

Nitric oxide (NO) is a bioactive gas that has multiple roles in innate and adaptive immune responses. In macrophages, nitric oxide is produced by inducible nitric oxide synthase upon microbial and cytokine stimulation. It is needed for host defense against pathogens and for immune regulation. This review will summarize the role of NO and iNOS in inflammatory and immune responses and will discuss the regulatory mechanisms that control inducible nitric oxide synthase expression and activity.

Epitope Specificity of Anti-Citrullinated Protein Antibodies

Anti-citrullinated protein antibodies are primarily associated with a progressive course in the autoimmune disease rheumatoid arthritis, a disease with a chronic and inflammatory nature. These antibodies do not appear to have any strict dependency for reactivity except from the presence of the non-genetically encoded amino acid citrulline, which is the result of a posttranslational modification, catalyzed by calcium-dependent peptidylarginine deiminase enzymes. Nevertheless, several amino acids surrounding the citrulline residue notably influence antibody reactivity, especially with a central-Cit-Gly-motif being essential for antibody reactivity. Most importantly, these antibodies have been proposed to be divided into two groups, based on their ability to recognize multiple citrullinated peptides. Thus, an "overlapping" antibody group, which appears to recognize several citrullinated peptides, and a "non-overlapping" antibody group, which only recognizes a limited number of citrullinated peptides, have been proposed. Based on these findings, we suggest that antibodies recognizing several citrullinated targets, also referred to as cross-reactive antibodies, primarily are backbone-dependent, whereas less cross-reactive antibodies primarily depend on the side chains of the amino acids comprising the epitopes for stable antibody-antigen interactions, which reduces the degree of cross-reactivity significantly. Clarifying the reactivity pattern of anti-citrullinated protein antibodies may contribute to determining their true nature of origin.

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

AIM

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Cellular electrophysiological principles that modulate secretion from synovial fibroblasts

Rheumatoid arthritis (RA) is a progressive disease that affects both pediatric and adult populations. The cellular basis for RA has been investigated extensively using animal models, human tissues and isolated cells in culture. However, many aspects of its aetiology and molecular mechanisms remain unknown. Some of the electrophysiological principles that regulate secretion of essential lubricants (hyaluronan and lubricin) and cytokines from synovial fibroblasts have been identified. Data sets describing the main types of ion channels that are expressed in human synovial fibroblast preparations have begun to provide important new insights into the interplay among: (i) ion fluxes, (ii) Ca²⁺ release from the endoplasmic reticulum, (iii) intercellular coupling, and (iv) both transient and longer duration changes in synovial fibroblast membrane potential. A combination of this information, knowledge of similar patterns of responses in cells that regulate the immune system, and the availability of adult human synovial fibroblasts are likely to provide new pathophysiological insights.

1, 25-dihydroxy-vitamin D3 with tumor necrosis factor-alpha protects against rheumatoid arthritis by promoting p53 acetylation-mediated apoptosis via Sirt1 in synoviocytes

Impaired apoptosis of fibroblast-like synoviocytes (FLSs) causes synovial hyperplasia, facilitating destruction of cartilage and bone in rheumatoid arthritis (RA). Tumor necrosis factor (TNF)-α, a dominant inflammatory mediator in RA pathogenesis, promotes progression of RA symptoms. Prevalence of 1, 25-dihydroxy-vitamin D₃ (hereafter termed VD) deficiency is 30-63% in patients with RA. Whether VD leads to apoptosis or enhances TNF-α-mediated apoptosis in FLSs to ameliorate RA is unclear. To determine this, 10-week-old CYP27B1-deficient (CYP27B1^-/-) mice with collagen-induced arthritis (CIA) were intraperitoneally treated with 1 μg/kg VD every other day for 9 weeks. RA phenotypes were compared between vehicle-treated CYP27B1^-/- and wild-type CIA mice. Human rheumatoid FLS-MH7A cells were treated with Dulbecco's modified Eagle's medium (DMEM) without fetal bovine serum (FBS) for 24 h, then with different concentrations of VD and TNF-α, human vitamin D receptor (VDR) siRNA or the p53 pro-apoptotic inhibitor pifithrin-α. Apoptosis and p53 pro-apoptotic signaling were analyzed. The 19-week-old vehicle-treated CYP27B1^-/- CIA mice had increased cumulative arthritis scores and levels of serous rheumatoid factors and C-reactive protein. They had exacerbated articular cartilage and bone destruction, joint space narrowing, joint stiffness, deformity and dysfunction, synovitis and TNF-α secretion, FLS hyperplasia with increased proliferation and decreased apoptosis compared to CIA mice. These RA phenotypes that were aggravated in CIA mice by CYP27B1 deficiency were largely rescued by VD treatment. In vitro, VD with TNF-α treatment upregulated p53 acetylation-mediated apoptosis in MH7A cells by promoting Sirt1 translocation from the nucleus to the cytoplasm. These findings indicated that VD with TNF-α protected against RA by promoting apoptosis of FLSs. The results indicated that clinical administration of VD could be a specific therapy to promote FLS apoptosis and prevent RA progression.

Pharmacological studies on the anti-inflammatory and immunomodulatory role of pentoxifylline and its interaction with nitric oxide (NO) in experimental arthritis in rats

AIM

Present study was designed to evaluate protective effects of pentoxifylline and its potentiation with low dose of nitric oxide (NO) modulators in adjuvant-induced experimental arthritis in rats.

METHOD

Wistar rats (200-300 g, n = 8 per group) of both sexes were used in the study. On day "0" experimental arthritis was induced by injecting 0.2 ml of Complete Freund's adjuvant (CFA) in sub-planter region of right hind paw of animals. Pentoxifylline treatment alone and in combination with NO modulators was given (i.p.) from day 14 to 28. Various arthritic parameters were recorded and blood and joint synovial fluid was collected for biochemical analysis.

RESULTS

CFA inoculation significantly increases (1) arthritic index (2) ankle diameter (3) paw volume (4) histopathology score (5) serum TNF-α, IL-6, IL-1β and synovial TNF-α levels (p < 0.001) (6) serum Th₁ and Th₂ cytokine levels g) MDA levels in rat paw tissue homogenates (7) serum NF-κB levels. Significant decrease in serum IL-10 levels and SOD activity was observed in rats after CFA inoculation. Decrease in body weight and suppressed general quality of life of CFA inoculated rats was also observed. These CFA-induced arthritic changes were significantly reversed by pentoxifylline alone and in combination with low dose of NO modulators (p < 0.05).

CONCLUSION

These results are suggestive of protective effects of pentoxifylline and its potentiation in combination with low dose of NO modulators. These results may provide new pharmacological therapy for management of rheumatoid arthritis (RA).

Interleukin-35 (IL-35) inhibits proliferation and promotes apoptosis of fibroblast-like synoviocytes isolated from mice with collagen-induced arthritis

Rheumatoid arthritis (RA) is an inflammatory disorder of the joints that affects 0.5-1 % of adults. Excessive growth of the fibroblast-like synoviocytes (FLS) promotes hyperplasia of synovial tissues and causes its invasion into the bone and cartilage, which eventually causes deformity and dysfunction of affected joints. Interleukin 35 (IL-35) was shown to suppress the inflammatory responses to collagen-induced arthritis (CIA) via upregulation of T regulatory cells and suppression of T helper type 17 cells in a mouse model. To study the effects of IL-35 on the proliferation and apoptosis frequency of cultured FLS isolated from mice with CIA as well as to examine the effects of IL-35 on CIA in vivo. Thirty DBA/1 J mice, which are used as an animal model for RA, were divided randomly (ten mice per group) to a CIA group (collagen treatment), a CIA + IL-35 group (collagen and IL-35 treatments), and a control group (no treatment). Starting on the 24th day after collagen administration, IL-35 was injected intraperitoneally into mice of the CIA + IL-35 group once per day for 10 days. An arthritis index was calculated, and pathological analysis of synovial tissue was performed. FLS isolated from CIA mice were treated with various concentrations of IL-35 (12.5-100 ng/ml). The MTT assay was used to examine FLS proliferation, and apoptosis frequency of FLS was detected by flow cytometry. On day 24, the CIA mice began to exhibit arthritis symptoms, and the symptoms rapidly progressed with time. Treatment with IL-35 significantly alleviated arthritis symptoms and reduced the synovial tissue inflammation. In addition, IL-35 treatment inhibited proliferation and promoted apoptosis in cultured FLS from CIA mice in a dose-dependent manner. IL-35 could ameliorate the symptoms of arthritis in the CIA mouse model in vivo and inhibited FLS proliferation while promoting FLS apoptosis in vitro, thereby exhibited the potential in inhibiting the progression of RA.

In vivo anti-inflammatory activities of the essential oil from Radix Angelicae dahuricae

Although Radix Angelicae dahuricae (Angelica) has been traditionally used in patients with rheumatism arthralgia, its bioactive ingredients remain to be determined. In this study, the essential oil extract of Radix Angelicae dahuricae (EOAD) was assessed for its anti-inflammatory activities against xylene-induced acute ear swelling and carrageenan-induced acute paw edema in mice as well as its anti-inflammatory and immunomodulating properties in Freund's complete adjuvant (FCA)-induced arthritis in rats. We found that EOAD at 100 mg/kg significantly alleviated xylene-induced ear swelling and carrageenan-induced paw edema in mice. Moreover, in the FCA-induced rat arthritis model, EOAD significantly improved hind paw swelling, lowered the adjuvant arthritis score, mitigated synovial hyperplasia, inflammatory cell infiltration, and cartilage destruction in the ankle joint, and reduced the serum levels of inflammatory mediators such as nitric oxide, tumor necrosis factor-α, and prostaglandin E2 as well as serum nitric oxide synthase activity. These findings support the fact that the essential oil extract of Angelica contains important active constituents responsible for its anti-inflammatory activities and therefore help to understand the phytotherapeutic effects of Angelica in the treatment of aseptic inflammation.

microRNA-126 targeting PIK3R2 promotes rheumatoid arthritis synovial fibro-blasts proliferation and resistance to apoptosis by regulating PI3K/AKT pathway

OBJECTIVE

The purpose of our study was to elucidate the impact of microRNA-126 (miR-126) targeting PIK3R2 gene on cell proliferation and apoptosis of rheumatoid arthritis synovial fibro-blasts (RASFs) by regulating PI3K/AKT signal pathway.

METHODS

The synovial tissue samples of this study were from 55 RA patients undergoing joint replacement and 27 healthy people undergoing joint repair due to trauma. The target genes of miR-126 were collected by the TargetScan and PIK3R2 as the direct target gene of miR-126 was confirmed by dual-luciferase reporter assay system. Our experiment had five groups including the blank control, miR-126 mimic, miR-126 mimic control, miR-126 inhibitor and miR-126 inhibitor control groups. Additionally, real-time quantitative polymerase chain reaction (RT-qPCR), Western-Blot, cell counting kit (CCK-8) and flow cytometry were carried out in this study.

RESULTS

Compared with healthy individuals, the RA patients had increased miR-126, but decreased PIK3R2 mRNA expressions in the synovial tissues. Pearson correlation analysis indicated that miR-126 expression was negatively correlated with PIK3R2 mRNA expression (all P<0.05). When compared with the blank group respectively, the miR-126 mimic group had raising cell proportions in S and G2/M phases with reduced rate of cell apoptosis, while the miR-126 inhibitor group had raising cell proportions in G0/G1 and G2/M phases with increased rate of cell apoptosis (all P<0.05). Besides, compared with the blank control group, the miR-126 mimic group had declined expression of PIK3R2 protein with ascended expression of PI3K and p-AKT (all P<0.05), while the miR-126 inhibitor group had increased expression of PIK3R2 protein with decreased expression of PI3K and p-AKT (all P<0.05).

CONCLUSION

Our study demonstrated that down-regulation of miR-126 may indirectly inhibit PI3K/AKT signaling pathway to disrupt the imbalance between growth and death of RASFs by targeting PIK3R2, which may be clinically helpful to find therapeutic strategies directed toward miR-126 function for RA patients.