Long Noncoding RNA HAFML Promotes Migration and Invasion of Rheumatoid Fibroblast-like Synoviocytes.

The aggressive phenotype exhibited by fibroblast-like synoviocytes (FLSs) is critical for the progression of joint destruction in rheumatoid arthritis (RA). Long noncoding RNAs (lncRNAs) have crucial roles in the pathogenesis of diverse disorders; however, few have been identified that might be able to control the joint damage in RA. In this study, we identified an lncRNA, ENST00000509194, which was expressed at abnormally high levels in FLSs and synovial tissues from patients with RA. ENST00000509194 positively modulates the migration and invasion of FLSs by interacting with human Ag R (HuR, also called ELAVL1), an RNA-binding protein that mainly stabilizes mRNAs. ENST00000509194 binds directly to HuR in the cytoplasm to form a complex that promotes the expression of the endocytic adaptor protein APPL2 by stabilizing APPL2 mRNA. Knockdown of HuR or APPL2 impaired the migration and invasion of RA FLSs. Given its close association with HuR and FLS migration, we named ENST00000509194 as HAFML (HuR-associated fibroblast migratory lncRNA). Our findings suggest that an increase in synovial HAFML might contribute to FLS-mediated rheumatoid synovial aggression and joint destruction, and that the lncRNA HAFML might be a potential therapeutic target for dysregulated fibroblasts in a wide range of diseases.

NAT10 promotes synovial aggression by increasing the stability and translation of N4-acetylated PTX3 mRNA in rheumatoid arthritis.

OBJECTIVE: Recent studies indicate that N-acetyltransferase 10 (NAT10)-mediated ac4C modification plays unique roles in tumour metastasis and immune infiltration. This study aimed to uncover the role of NAT10-mediated ac4C in fibroblast-like synoviocytes (FLSs) functions and synovial immune cell infiltration in rheumatoid arthritis (RA). METHODS: FLSs were obtained from active established patients with RA. Protein expression was determined by western blotting or immunohistochemistry or multiplexed immunohistochemistry. Cell migration was measured using a Boyden chamber. ac4C-RIP-seq combined with RNA-seq was performed to identify potential targets of NAT10. RNA immunoprecipitation was used to validate the interaction between protein and mRNA. NAT10 haploinsufficiency, inhibitor remodelin or intra-articular Adv-NAT10 was used to suppress arthritis in mice with delayed-type hypersensitivity arthritis (DYHA) and collagen II-induced arthritis (CIA) and rats with CIA. RESULTS: We found elevated levels of NAT10 and ac4C in FLSs and synovium from patients with RA. NAT10 knockdown or specific inhibitor treatment reduced the migration and invasion of RA FLSs. Increased NAT10 level in the synovium was positively correlated with synovial infiltration of multiple types of immune cells. NAT10 inhibition in vivo attenuated the severity of arthritis in mice with CIA and DTHA, and rats with CIA. Mechanistically, we explored that NAT10 regulated RA FLS functions by promoting stability and translation efficiency of N4-acetylated PTX3 mRNA. PTX3 also regulated RA FLS aggression and is associated with synovial immune cell infiltration. CONCLUSION: Our findings uncover the important roles of NAT10-mediated ac4C modification in promoting rheumatoid synovial aggression and inflammation, indicating that NAT10 may be a potential target for the treatment of RA, even other dysregulated FLSs-associated disorders.

Piperlongumine inhibits the proliferation, migration and invasion of fibroblast-like synoviocytes from patients with rheumatoid arthritis.

OBJECTIVES: Recent studies have indicated that piperlongumine (PLM) may exert anti-inflammatory effects. In the present study, we determined the effect of PLM on the proliferation, apoptosis, migration and invasion of fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis (RA) (referred to herein as RA FLS). We further explored the mechanisms by which the studied compound inhibits the functions of RA FLS. METHODS: RA FLS viability and apoptosis were tested using MTT and Annexin V/PI assays, respectively. We performed an EDU assay to examine the proliferation of RA FLS. The migration and invasion of these cells were measured using a transwell chamber method and wound closure assay. The MMP-1, MMP-3, and MMP-13 levels in the culture supernatants of RA FLS were detected using a Luminex Assay kit. The intracellular ROS levels were detected using DCFH-DA. The expression levels of signal transduction proteins were measured using western blot. RESULTS: We found that PLM induced apoptosis in RA FLS at concentrations of 15 and 20 µM. The proliferation of RA FLS was downregulated by PLM at concentrations of 1, 5 and 10 µM. Migration and invasion of RA FLS were reduced by PLM at concentrations of 1, 5 and 10 µM. PLM also inhibited cytoskeletal reorganization in migrating RA FLS and decreased TNF-α-induced intracellular ROS production. Moreover, we demonstrated the inhibitory effect of PLM on activation of the p38, JNK, NF-κB and STAT3 pathways. CONCLUSIONS: Our findings suggest that PLM can inhibit proliferation, migration and invasion of RA FLS. Moreover, these data suggests that PLM might have therapeutic potential for the treatment of RA.

Piperlongumine Suppresses Dendritic Cell Maturation by Reducing Production of Reactive Oxygen Species and Has Therapeutic Potential for Rheumatoid Arthritis.

Piperlongumine (PLM) is a natural product from the plant Piper longum that inhibits platelet aggregation, atherosclerosis plaque formation, and tumor cell growth. It has potential value in immunomodulation and the management of autoimmune diseases. In this study, we investigated the role of PLM in regulating the differentiation and maturation of dendritic cells (DCs), a critical regulator of immune tolerance, and evaluated its clinical effects in a rheumatoid arthritis mouse model. We found that PLM treatment reduced LPS-induced murine bone marrow-derived DC maturation, characterized by reduced expression of CD80/86, secretion of MCP-1, IL-12p70, IL-6, TNFα, IFN-γ, and IL-23, and reduced alloproliferation of T cells; however, PLM does not affect cell differentiation. Furthermore, PLM reduced intracellular reactive oxygen species (ROS) production by DCs and inhibited the activation of p38, JNK, NF-κB, and PI3K/Akt signaling pathways. Conversely, PLM increased the expression of GSTP1 and carbonyl reductase 1, two enzymes that counteract ROS effects. ROS inhibition by exogenous N-acetyl-l-cysteine suppressed DC maturation. PLM treatment improved the severity of arthritis and reduced in vivo splenic DC maturation, collagen-specific CD4(+) T cell responses, and ROS production in mice with collagen-induced arthritis. Taken together, these results suggest that PLM inhibits DC maturation by reducing intracellular ROS production and has potential as a therapeutic agent for rheumatoid arthritis.

Protein Inhibitor of Activated STAT3 Regulates Migration, Invasion, and Activation of Fibroblast-like Synoviocytes in Rheumatoid Arthritis.

The aggressive phenotype displayed by fibroblast-like synoviocytes (FLSs) is a critical factor of cartilage destruction in rheumatoid arthritis (RA). Increased FLSs migration and subsequent degradation of the extracellular matrix are essential to the pathology of RA. Protein inhibitor of activated STAT (PIAS), whose family members include PIAS1, PIAS2 (PIASx), PIAS3, and PIAS4 (PIASy), play important roles in regulating various cellular events, such as cell survival, migration, and signal transduction in many cell types. However, whether PIAS proteins have a role in the pathogenesis of RA is unclear. In this study, we evaluated the role of PIAS proteins in FLSs migration, invasion, and matrix metalloproteinases (MMPs) expression in RA. We observed increased expression of PIAS3, but not PIAS1, PIAS2, or PIAS4, in FLSs and synovial tissues from patients with RA. We found that PIAS3 knockdown by short hairpin RNA reduced migration, invasion, and MMP-3, MMP-9, and MMP-13 expression in FLSs. In addition, we demonstrated that PIAS3 regulated lamellipodium formation during cell migration. To gain insight into molecular mechanisms, we evaluated the effect of PIAS3 knockdown on Rac1/PAK1 and JNK activation. Our results indicated that PIAS3-mediated SUMOylation of Rac1 controlled its activation and modulated the Rac1 downstream activity of PAK1 and JNK. Furthermore, inhibition of Rac1, PAK1, or JNK decreased migration and invasion of RA FLSs. Thus, our observations suggest that PIAS3 suppression may be protective against joint destruction in RA by regulating synoviocyte migration, invasion, and activation.

Bromodomain and extra-terminal domain bromodomain inhibition prevents synovial inflammation via blocking IκB kinase-dependent NF-κB activation in rheumatoid fibroblast-like synoviocytes.

OBJECTIVE: To explore the roles of the bromodomain (Brd) and extra-terminal domain (BET) of chromatin adaptors in regulating synovial inflammation in RA. METHODS: Fibroblast-like synoviocytes (FLSs) were isolated from synovial tissue from RA patients. A specific BET inhibitor, JQ1, and short hairpin RNA (shRNA) for Brd2 or Brd4 were used to evaluate the role of the BET Brd in inflammatory responses. Protein expression was measured by western blot or immunofluorescence staining. Nuclear factor kappa B (NF-κB) gene activity was detected by luciferase assay. The secretion and gene expression of cytokines and MMPs were evaluated by ELISA and real-time PCR, respectively. FLS proliferation was detected by BrdU incorporation. RESULTS: Four Brd proteins, including Brd2, Brd3, Brd4 and Brdt, were expressed in FLSs from patients with RA and OA; however, the expression of Brd2 and Brd4 was increased in RA compared with that in OA. Treatment with JQ1, Brd2 shRNA or Brd4 shRNA decreased the production of pro-inflammatory cytokines (TNFα, IL-1ß, IL-6 and IL-8), MMPs expression (MMP-1, MMP-3 and MMP-13) and proliferation by RA FLSs. BET inhibition downregulated TNFα-induced NF-κB-dependent transcription and expression of the NF-κB target genes. JQ1 suppressed the phosphorylation of IκB kinaseß and IκBα, and nuclear translocation of p65. Intraperitoneal injection of JQ1 in mice with collagen-induced arthritis reduced synovial inflammation, joint destruction and serum levels of the anti-CII antibodies TNFα and IL-6. CONCLUSION: This study implicates BET Brds as important regulators of IκB kinase/NF-κB-mediated synovial inflammation of RA and identifies BET proteins as novel therapeutic targets in inflammatory arthritis.

Factors Associated with Erosive Arthritis in Rheumatoid Arthritis and Other Connective Tissue Diseases: A Retrospective Study From a Southern Chinese Population.

OBJECTIVE: To investigate the clinical predictors of erosive arthritis (EA) in patients with rheumatoid arthritis (RA) and other connective tissue diseases. METHODS: Four hundred and one consecutive patients with newly diagnosed RA between January 2010 and January 2013 were enrolled in the study. During the study period, 729 consecutive patients with non-RA connective tissue diseases were also included, and a cross-sectional study was performed. Medical records were reviewed. Only those patients with data for 2 years were considered in the analysis (338). RESULTS: Erosive arthritis was noted in 60.4% (204 /338) of patients with RA and occurred early in RA. The multivariate logistic regression analysis indicated that rheumatoid nodules, anemia, and positive anticyclic citrullinated peptide antibody (ACPA) were strongly associated factors for the occurrence of EA in RA patients. Erosive arthritis was also noted in 1.5% of patients with SLE, 5.8% of patients with primary Sjögren syndrome, and 9.1% (3/33) of patients with systemic sclerosis. When compared with patients without EA, high level and prominently higher positive rate of ACPA was found in these patients with EA. On receiver operating characteristic curve analysis, ACPA exhibited a maximum sensitivity with a cutoff value of 1.6 U/mL and 0.6 U/mL for RA and SLE patients, respectively. CONCLUSION: Erosive arthritis had a high prevalence in Chinese RA patients and occurred early. Anemia, rheumatoid nodules, and ACPA were associated with EA in RA. Erosive arthritis also could be detected in SLE, primary Sjögren syndrome, and systemic sclerosis. Anticyclic citrullinated peptide antibodies were also associated with EA in these diseases. Intensive monitoring for erosions was recommended for RA patients with a cutoff of ACPA greater than 1.6 U/mL and greater than 0.6 U/mL for SLE patients.

Early-stage hip involvement in patients with ankylosing spondylitis: A Chinese study based on magnetic resonance imaging.

OBJECTIVES: To evaluate the clinical characteristics and identify potential factors of the early-stage hip involvement in patients with ankylosing spondylitis (AS) based on the magnetic resonance imaging (MRI). METHODS: A cross-sectional retrospective study of 655 consecutive patients was performed. Patients with hip pain or limited hip function but lacking definitive evidence of hip involvement on radiography underwent hip MRI. Based on the results of the imaging tests, the patients were classified into three categories: (1) no hip involvement; (2) early-stage hip involvement according to MRI but not radiography; (3) advanced-stage hip involvement according to a Bath Ankylosing Spondylitis Radiology Index-hip score ≥2. RESULTS: One hundred and sixty-eight patients had early-stage hip involvement and 103 patients had advanced-stage hip involvement. Multivariate logistic regression analysis indicated that younger age at onset, worse BASMI score, and more active inflammation in the sacroiliac joints were associated with the occurrence of early-stage hip involvement. CONCLUSION: Negative plain radiography results cannot be used to rule out hip involvement. MRI was superior to radiography for the detection of early-stage hip involvement. Susceptible AS patients with symptoms or risk factors for hip involvement should undergo hip MRI to test for lesions in the early stage.

Inhibitory effects of niclosamide on inflammation and migration of fibroblast-like synoviocytes from patients with rheumatoid arthritis.

OBJECTIVES: This study evaluated the anti-inflammatory effect of niclosamide in tumor necrosis factor (TNF)-α-stimulated human rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS) and inhibitory effects on migration and invasion in RA FLS and investigated the signal mechanism, and further explored the treatment activity of niclosamide on collagen-induced arthritis (CIA). METHODS: The levels of interleukin (IL)-1ß, IL-6, IL-8, IL-10,IL-17A and interferon (IFN)-γ in cultural supernatants were measured by multiplex cytokine assay kits. RA FLS migration and invasion in vitro were measured by the Boyden chamber method and the scratch assay. Signal transduction proteins expression was measured by western blot. The in vivo suppressive effects of niclosamide were elucidated on CIA in a mouse model. RESULTS: Niclosamide reduced the secretion of IL-1ß, IL-6, IL-8, IL-17A and IFN-γ from TNF-α-induced RA FLS in a dose-dependent manner. Niclosamide inhibits FBS-induced migration and invasion and exhibits F-actin alterations in RA FLS. Niclosamide decreased the phosphorylation of c-Jun N-terminal kinase and ERK in TNF-α-stimulated RA FLS and blocked TNF-α-induced IKK, IκBα phosphorylation and translocation of p65. Niclosamide treatments reduced the severity of CIA model. CONCLUSIONS: Our data suggest for the first time that niclosamide posses the anti-inflammatory effect in RA both in vitro and in vivo.

Niclosamide inhibits the inflammatory and angiogenic activation of human umbilical vein endothelial cells.

OBJECTIVE: Niclosamide is known to have anti-cancer and anti-inflammatory activities; however, its therapeutic mechanism has not been defined. In this study, to explain the therapeutic mechanism of niclosamide, we examined the effect of niclosamide on endothelial cell activation,leukocyte integration, proliferation, migration and angiogenesis in vitro. METHODS: Endothelia-leukocyte adhesion assays were used to assess primary cultures of human umbilical vein endothelial cells' (HUVECs) activation following TNF-α treatment. Each step of angiogenesis was evaluatedin vitro, including endothelial cell proliferation, migration and tube formation. Proliferation was examined using EdU assays, while wound migration assays and transwell assays were used to evaluate cell migration; cord like structure formation assays on Matrigel were used to assess tube formation. In vivo matrigel plug assay was used to assess angiogenesis. The protein expression was measured using western blot. RESULTS: Niclosamide reduced the adhesion of human monocyte cells to HUVECs. Niclosamide also reduced protein expression of VCAM-1 and ICAM1 in HUVECs.Niclosamide significantly inhibited HUVEC proliferation,migration and cord-like structure formation. Niclosamide also suppresses VEGF-induced angiogenesis in vivo.Niclosamide attenuated IKK-mediated activation of NF-κB pathway in TNFα-induced endothelial cells. Niclosamide also suppresses VEGF-induced endothelial VEGFR2 activation and downstream P-AKT, P-mTOR and P-p70S6K. CONCLUSIONS: Niclosamide exerted a potent effect on HUVECs activation, suggesting that it might function via an endothelia-based mechanism in the treatment of various diseases, including rheumatoid arthritis and cancer.

Increased phosphorylation of ezrin is associated with the migration and invasion of fibroblast-like synoviocytes from patients with rheumatoid arthritis.

OBJECTIVE: Increasing evidence indicates that the cytoskeletal protein ezrin may play a critical role in cell motility. This study aims to investigate the role of ezrin in regulating the migration and invasion of fibroblast-like synoviocytes (FLSs) from patients with RA. METHODS: Synovial tissues were obtained from 12 patients with RA and 6 with OA, and then FLSs were separated from synovial tissues. The expression of ezrin and phosphorylated ezrin (p-ezrin) was examined by Western blotting or IF staining. A specific inhibitor of ezrin phosphorylation and small interference RNA-mediated ezrin knockdown were used to inhibit the phosphorylation of ezrin. Migration and invasion of FLSs in vitro were measured by the Boyden chamber assay. RESULTS: Increased expression of p-ezrin protein was found in synovial tissue and FLSs in patients with RA compared with patients with OA. Stimulation with TNF-α and IL-1ß increased ezrin phosphorylation in RA FLSs. Inhibition of p-ezrin protein by a specific inhibitor of phosphorylation of ezrin and small interfering RNA-mediated knockdown reduced in vitro migration and invasion, as well as actin stress fibre formation in RA FLS. Furthermore, rho kinase and p38 mitogen-activated protein kinase (MAPK) signal pathways were involved in the phosphorylation of ezrin and invasion of RA FLSs. CONCLUSION: Increased expression of p-ezrin may contribute to aberrant aggressive behaviours of RA FLSs, which are mediated by rho kinase and the p38 MAPK pathway. This suggests a novel strategy targeting phosphorylation of ezrin to prevent synovial invasiveness and joint destruction in RA.

Coptisine inhibits aggressive and proliferative actions of fibroblast like synoviocytes and exerts a therapeutic potential for rheumatoid arthritis.

OBJECTIVE: Coptisine, a natural bioactive small molecular compound extracted from traditional Chinese herb Coptis chinensis, has been shown to exhibit anti-tumor effect. However, its contribution to autoimmune diseases such as rheumatoid arthritis (RA) is unknown. Here, we evaluate the effect of coptisine in controlling fibroblast-like synoviocytes (FLS)-mediated synovial proliferation and aggression in RA and further explore its underlying mechanism(s). METHODS: FLS were separated from synovial tissues obtained from patients with RA. Protein expression was measured by Western blot or immunohistochemistry. Gene expression was detected by quantitative RT-PCR. The EdU incorporation was used to measure cell proliferation. Migration and invasion were determined by Boyden chamber assay. RNA sequencing analysis was used to seek for the target of coptisine. The in vivo effect of coptisine was evaluated in collagen-induced arthritis (CIA) model. RESULTS: Treatment with coptisine reduced the proliferation, migration, and invasion, but not apoptosis of RA FLS. Mechanistically, we identified PSAT1, an enzyme that catalyzes serine/one-carbon/glycine biosynthesis, as a novel targeting gene of coptisine in RA FLS. PSAT1 expression was increased in FLS and synovial tissues from patients with RA compared to healthy control subjects. Coptisine treatment or PSAT1 knockdown reduced the TNF-α-induced phosphorylation of p38, ERK1/2, and JNK MAPK pathway. Interestingly, coptisine administration improved the severity of arthritis and reduced synovial PSAT1 expression in mice with CIA. CONCLUSIONS: Our data demonstrate that coptisine treatment suppresses aggressive and proliferative actions of RA FLS by targeting PSAT1 and sequential inhibition of phosphorylated p38, ERK1/2, and JNK MAPK pathway. Our findings suggest that coptisine might control FLS-mediated rheumatoid synovial proliferation and aggression, and be a novel potential agent for RA treatment.

ALKBH5-Mediated RNA m6 A Methylation Regulates the Migration, Invasion, and Proliferation of Rheumatoid Fibroblast-Like Synoviocytes.

OBJECTIVE: Fibroblast-like synoviocytes (FLSs) are critical for promoting joint damage in rheumatoid arthritis (RA). N6 -methyladenosine (m6 A) modification plays key roles in various diseases, but its role in the pathogenesis of RA is largely unknown. Here, we investigate increased demethylase ALKBH5 promotion of proliferation, migration, and invasion of RA FLSs via regulating JARID2 expression. METHODS: ALKBH5 expression in FLSs was evaluated using real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot. 5-ethynyl-2'-deoxyuridine, scratch wound healing, and transwell assays were implemented to determine the role of ALKBH5 on RA FLS proliferation, mobility, and migration. Then, m6 A sequencing combined with RNA sequencing was performed to identify the potential targets of ALKBH5. RNA immunoprecipitation and RNA pulldown were then used to validate the interaction between the protein and messenger RNA (mRNA). Collagen-induced arthritis (CIA) and delayed-type hypersensitivity arthritis (DTHA) models were further established to assess the therapeutic potency of ALKBH5 in vivo. RESULTS: We demonstrated that ALKBH5 expression was increased in FLSs and synovium from RA. Functionally, ALKBH5 knockdown inhibited the proliferation, migration, and invasion of RA FLSs, whereas overexpression of ALKBH5 displayed the opposite effect. Mechanistically, ALKBH5 mediated m6 A modification in the JARID2 mRNA and enhanced its mRNA stability in cooperation with IGF2BP3. Intriguingly, the severity of arthritis was attenuated in mice with DTHA and ALKBH5 knockout or rats with CIA and intra-articular injection of ALKBH5 short hairpin RNA. CONCLUSION: Our findings suggest that ALKBH5-mediated m6 A modification is crucial for synovial hyperplasia and invasion in RA. ALKBH5 might be a potential therapeutic target for RA and even for dysregulated fibroblasts in a wide range of diseases.

Response to belimumab among patients with refractory lupus nephritis: a real-world observational retrospective multicenter study.

OBJECTIVES: Belimumab is a biological agent approved for the treatment of active lupus nephritis (LN), but its efficacy on refractory lupus nephritis (LN) is unknown. This study aims to evaluate the efficacy and safety of belimumab in Chinese patients with refractory LN. METHODS: This multicenter, observational, and retrospective study enrolled patients with refractory LN who failed induction therapy with steroids, cyclophosphamide, mycophenolate, and calcineurin inhibitors and received 24-week belimumab treatment before data analysis. Treatment outcomes include the overall clinical response (physician judgment, disease activity, organ damage) and renal response (complete renal response, partial renal response, no renal response). Laboratory indices and adverse events were recorded as well. RESULTS: Of the 45 patients enrolled in the study, 6 (13.3%) achieved complete renal response, 19 (42.2%) achieved partial renal response, and the overall renal response rate was 55.6%. Median rSLEDAI decreased from 12 (IQR 8-12) at baseline to 8 (IQR 4-8) (p < 0.0001), 4 (IQR 4-8) (p < 0.0001) at 12 and 24 weeks. Mean urinary protein decreased more than 50% from 3.2 g/24 h at baseline to 1.0 g/24 h at 24 weeks (p < 0.0001). The conditions of hypoalbuminemia and hypocomplementemia had also gradually improved. The levels of autoantibodies showed a significant downward trend. Additionally, 9 (20.0%) patients successfully reduced the dosage of prednisone to a safe range, and 3 of them achieved their treatment goal of prednisone cessation. The mean prednisone dosage decreased from 32.7 mg/day at baseline to 18.6 mg/day (p < 0.0001), 13.3 mg/day (p < 0.0001) at 12 and 24 weeks. There were 3 adverse events reported, including 2 cases of infection, and 1 case of allergy. No serious events occurred during the follow-up. CONCLUSIONS: Belimumab is effective and safe when used in clinical practice, which can be considered as an add-on therapy for refractory LN. Key Points • A multicenter observational study in the real clinical settings of China. • First revealed the efficacy and safety of belimumab in Chinese patients with refractory LN.

Inhibitory effects of simvastatin on migration and invasion of rheumatoid fibroblast-like synoviocytes by preventing geranylgeranylation of RhoA.

To investigate the effect of simvastatin on the migration and invasion of fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis (RA) and its cellular signal mechanisms, FLS from active RA patients were stimulated with 3 % FBS or GM-CSF in the presence or absence of simvastatin. Cells migration and invasion in vitro were measured by the Boyden chamber method. RhoA activity was assessed by a pull-down assay. Matrix metalloproteinases-2 (MMP-2) activity was evaluated by zymography. Simvastatin inhibits FBS- or GM-CSF-induced migration in a dose-dependent manner by RA FLS, and this inhibitory effect is independent of cell apoptosis. We also found that simvastatin suppressed in vitro invasion, adhesion, MMP-2 activity, cytoskeletal reorganization and RhoA activation. Furthermore, mevalonate or GGPP treatment reversed the inhibitory effect of simvastatin not only on migration and invasion in vitro but also on RhoA activation, and inhibition of RhoA by specific siRNA transfection reduced migration, adhesion and invasion of RA FLS. This study shows that simvastatin reduces RA FLS migration and invasion through the prevention of protein geranylgeranylation and RhoA activation. These findings provide a novel evidence that statin may be benefit for preventing RA arthritic destruction, and also indicate that RhoA may be a new target for the modulation of RA FLS migration and invasion.

Clinical features and independent predictors in the further development of rheumatoid arthritis in undifferentiated arthritis.

This study aims to investigate the prognosis of undifferentiated arthritis (UA) and to estimate the putative predictors contributing to predict the development of UA into rheumatoid arthritis (RA); thus, it could improve appropriate medical intervention. A retrospective cohort study of 218 patients with an initial diagnosis of UA and 2-year follow-up monitoring was carried out. The baseline information including demographic variables, clinical features, and laboratory data was collected. A logistic regression model was used for the statistical analysis. After 2 years of follow-up, 20.18% of UA patients evolved into RA, but 33.03% remained undifferentiated. Meanwhile, 25.23% went into remission, and 21.56% developed into other connective tissue diseases. Univariate and multivariate analysis showed that the titer of antibodies to cyclic citrullinated peptide (anti-CCP), tender joint count and duration of morning stiffness were independent predictors for the development of RA. The area under the curve (AUC) of duration of morning stiffness (0.81) was largest, followed by tender joint count (0.74). The AUC of anti-CCP antibodies (0.68) was higher than that of rheumatoid factor of IgM type (IgM-RF) (0.60), and the combination of these two antibodies was significantly higher than each alone (P < 0.001). In conclusion, UA patients had variable clinical outcomes and prognosis. Only the titer of anti-CCP antibodies, tender joint count, and duration of morning stiffness, instead of IgM-RF, could predict the development of RA. Although the anti-CCP antibody was better than the IgM-RF in predicting RA, a combined detection of them still improved the diagnostic performance.

[Modulation of RhoA/Rho kinase on migration, invasion and proliferation of fibroblast like synoviocytes from patients with rheumatoid arthritis].

OBJECTIVE: To evaluate the modulation of RhoA/Rho kinase (ROCK), a small Rho GTPase, on migration, invasion and proliferation of fibroblast like synoviocytes (FLS) from rheumatoid arthritis (RA) patients. METHODS: RA FLS were collected from active RA patients. And 10% fetal bovine serum (FBS) and interleukin-1ß (IL-1ß) were used as stimuli in migration and proliferation experiments respectively. RhoA activity was measured by pull down assay while ROCK activity by Western blot. FLS migration and invasion in vitro were measured by the Transwell chamber method. And thiazolyl blue tetrazolium bromide (MTT) test was used to detect cell proliferation. RESULTS: There were increased activities of RhoA and ROCK in ex vivo FLS from RA versus OA patients and healthy control. The migrated cell number of FBS-induced, C3-treated and Y27632-treated groups was 85 ± 14, 51 ± 15 and 42 ± 11 respectively. The Matrigel invading cell number of 3 groups was 64 ± 13, 39 ± 12 and 26 ± 9 respectively. Statistical differences existed in cell number between FBS-induced, C3-treated or Y27632-treated group (P < 0.05) in above migration and invasion experiments. Inhibition of RhoA and ROCK activity also suppressed the cytoskeletal reorganization and proliferation of RA FLS. CONCLUSION: Increased RhoA/ROCK activity may contribute to abnormal migration, invasion and proliferation of RA FLS. Thus inhibition of ROCK activity may be a new therapeutic target for RA.

Schisandrin treatment suppresses the proliferation, migration, invasion, and inflammatory responses of fibroblast-like synoviocytes from rheumatoid arthritis patients and attenuates synovial inflammation and joint destruction in CIA mice.

BACKGROUND: Rheumatoid arthritis (RA) is a systemic autoimmune disease causing joint dysfunction. As disease-modifying anti-rheumatic drugs (DMARDs) have poor efficacy in 20% to 25% of RA patients, additional novel RA medications are urgently needed. Schisandrin (SCH) has multiple therapeutic effects. However, whether SCH is effective against RA remains unknown. PURPOSE: To investigate how SCH affects the abnormal behaviours of RA fibroblast-like synoviocytes (FLSs) and further elucidate the underlying mechanism of SCH in RA FLSs and collagen-induced arthritis (CIA) mice. METHODS: Cell Counting Kit-8 (CCK8) assays were used to characterize cell viability. EdU assays were performed to assess cell proliferation. Annexin V-APC/PI assays were used to determine apoptosis. Transwell chamber assays were used to measure cell migration and invasion in vitro. RT-qPCR was used to assess proinflammatory cytokine and MMP mRNA expression. Western blotting was used to detect protein expression. RNA sequencing was performed to explore the potential downstream targets of SCH. CIA model mice were used to assess the treatment efficacy of SCH in vivo. RESULTS: Treatments with SCH (50, 100, and 200 µΜ) inhibited RA FLSs proliferation, migration, invasion, and TNF-α-induced IL-6, IL-8, and CCL2 expression in a dose-dependent manner but did not affect RA FLSs viability or apoptosis. RNA sequencing and Reactome enrichment analysis indicated that SREBF1 might be the downstream target in SCH treatment. Furthermore, knockdown of SREBF1 exerted effects similar to those of SCH in inhibiting RA FLSs proliferation, migration, invasion, and TNF-α-induced expression of IL-6, IL-8, and CCL2. Both SCH treatment and SREBF1 knockdown decreased activation of the PI3K/AKT and NF-κB signalling pathways. Moreover, SCH ameliorated joint inflammation and cartilage and bone destruction in CIA model mice. CONCLUSION: SCH controls the pathogenic behaviours of RA FLSs by targeting SREBF1-mediated activation of the PI3K/AKT and NF-κB signalling pathways. Our data suggest that SCH inhibits FLS-mediated synovial inflammation and joint damage and that SCH might have therapeutic potential for RA.

Role of p21-activated kinase 1 in regulating the migration and invasion of fibroblast-like synoviocytes from rheumatoid arthritis patients.

OBJECTIVE: To investigate the role of p21-activated kinase 1 (PAK1) in regulating migration, invasion and MMP expression in RA fibroblast-like synoviocytes (FLS). METHODS: RA FLS migration and invasion in vitro were measured by the Boyden chamber method. Invasion of RA FLS into cartilage was detected in the severe combined immunodeficiency (SCID) mouse co-implantation model of RA in vivo. PAK1 and MT1-MMP expression were examined by western blotting. ELISA was used to measure the production and activity of MMPs. RESULTS: Phosphorylated PAK1 (p-PAK1) protein expression was increased in ex vivo synovial membrane cells from RA patients. Stimulation with IL-1ß or TNF-α up-regulated p-PAK1 expression. Inhibition of PAK1 by transfection with dominant negative PAK1 mutant (dnPAK1) reduced in vitro migration and invasion of RA FLS. In the SCID mouse model, RA FLS invasion into cartilage was attenuated by transfection with dnPAK1 in vivo. PAK1 regulated IL-1ß-induced production and activity of MMP-13 and MT1-MMP. Inhibition of MMP-13 or MT1-MMP activity also reduced RA FLS invasion. Furthermore, dnPAK1 transfection inhibited c-Jun N-terminal kinase (JNK) activation, but did not affect the activities of extracellular signal-regulated kinases and p38. Inhibition of the JNK activity by chemical inhibitor significantly reduced the migration, invasion and production of MMP-13 and MT1-MMP. CONCLUSION: PAK1 plays an important role in regulating the migration, invasion and production and activity of MMPs in RA FLS, which is mediated by the JNK pathway. This suggests a novel strategy targeting PAK1 to prevent joint destruction of RA.

cGAS/STING signaling in the regulation of rheumatoid synovial aggression.

Background: Fibroblast-like synoviocytes (FLSs) play a critical role in promoting synovial aggression and joint destruction in rheumatoid arthritis (RA). Cyclic GMP-AMP synthase (cGAS)/stimulator of interferon gene (STING) signaling plays an important role in controlling a series of cellular biological processes. However, it is still unclear whether cGAS/STING signaling regulates rheumatoid synovial aggression. Methods: Cell migration and invasion were detected using a Transwell chamber. Gene expression was measured using quantitative reverse transcription-polymerase chain reaction (qRT-PCR), and protein expression was detected by western blotting. Reactive oxygen species (ROS) levels were measured by 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) probe. F-actin staining and immunofluorescence assays were used to investigate lamellipodia formation and nuclear translocation, respectively. A severe combined immunodeficiency (SCID) mouse model was established to observe the migration and invasion of RA FLSs in vivo. Results: Our results showed that cytosolic double-stranded DNA (dsDNA)-induced cGAS/STING activation promoted the in vitro migration and invasion of RA FLSs. Moreover, RA FLSs treated with cGAS or STING short hairpin RNA (shRNA) exhibited reduced invasion into cartilage in the SCID model. Mechanistically, we determined that cGAS/STING activation leads to increased mitochondrial ROS levels, and thereby increases phosphorylation of mammalian sterile 20-like kinase 1 (MST1), a core component of the Hippo pathway, subsequently promoting activation of forkhead box1 (FOXO1). MST1 and FOXO1 knockdown also diminished the migration and invasion of RA FLSs. Conclusions: Our findings suggest that cGAS/STING signaling has an important role in regulating rheumatoid synovial aggression and that targeting cGAS/STING may represent a novel potential therapy for RA.