Qian Qiu

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-1β, 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 kinaseβ 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.

Lupus mesenteric vasculitis: Clinical features and associated factors for the recurrence and prognosis of disease

OBJECTIVE To evaluate the clinical characteristics of lupus mesenteric vasculitis (LMV) and identify the potential factors and appropriate treatments that are associated with disease relapse and prognosis in LMV. METHODS A retrospective cohort study was performed among patients admitted to the First Affiliated Hospital of Sun Yet-sen University between 2002 and 2011. Demographic information, clinical symptoms, laboratory findings, imaging characteristics like abdominal CT scan, ultrasonography, medications including corticosteroid, cyclophosphamide, and other immunosuppressive agents, and outcomes were documented. The endpoints of the study were defined as occurrence of severe complications that needed surgical intervention, disease recurrence, or death. RESULTS Out of 3823 systemic lupus erythematosus (SLE) patients, 97 were diagnosed with mesenteric vasculitis with the overall prevalence of 2.5%. Among these 97 LMV patients, 13 died because of serious complications (13/97, 13.4%) and 2 presented intestinal perforation during the induction therapy stage. The logistic regression multivariate analysis indicated that leukopenia [peripheral WBC, odds ratio (OR) = 0.640, 95% confidence interval (CI): 0.456-0.896, P = 0.009], hypoalbuminemia (serum albumin, OR = 0.891, 95% CI: 0.798-0.994, P = 0.039) and elevated serum amylase (OR = 7.719, 95% CI: 1.795-33.185, P = 0.006) were positively associated with the occurrence of serious complications, while intravenous cyclophosphamide (CYC) therapy inhibited the occurrence of serious complications (OR = 0.220, 95% CI: 0.053-0.903, P = 0.036). A total of 79 patients who achieved remission were followed-up for 2-96 months and 18 cases experienced disease relapse (18/79, 22.8%). The statistical analysis adjusted by Cox proportional hazards models indicated that high-dose CYC therapy (≥ 1.0 g/m(2)/month) was a protective factor for disease relapse and led to better outcomes [hazard ratio (HR) = 0.209, 95% CI: 0.049-0.887, P = 0.034], while the severe thickness of the bowel wall (>8mm) was a risk factor (HR = 7.308, 95% CI: 1.740-30.696, P = 0.007). LMV and lupus cystitis occurred concurrently in 22 (22/97, 22.7%) patients, and the symptoms of urinary tract resolved after treatment with corticosteroid and immunosupressants. CONCLUSION LMV is one of the serious complications of SLE with high mortality. The current study demonstrated that leukopenia, hypoalbuminemia, and elevated serum amylase were associated with severe adverse events, while CYC therapy led to better outcomes during remission-induction stage. Severe thickness of the bowel was a risk factor while high-dose CYC therapy was a protective factor for disease relapse in intensification therapy stage. It is necessary to evaluate the urinary tract involvement once LMV is diagnosed due to the frequent coexistence of these 2 diseases.

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.

BET Bromodomain Suppression Inhibits VEGF-induced Angiogenesis and Vascular Permeability by Blocking VEGFR2-mediated Activation of PAK1 and eNOS

The tyrosine kinase receptor vascular endothelial growth factor receptor 2 (VEGFR2) is a critical modulator of angiogenesis. Increasing evidence indicate the important role of bromodomain and extra-terminal domain (BET) of chromatin adaptors in regulating tumor growth and inflammatory response. However, whether BET proteins have a role in angiogenesis and endothelial permeability is unclear. In this study, we observed that treatment with JQ1, a specific BET inhibitor, suppressed in vitro tube formation of human umbilical vein endothelial cells (HUVECs) and in vivo angiogenesis in a Matrigel plug and oxygen-induced retinopathy neovascularization. JQ1 attenuated the VEGF-induced decrease in TEER in HUVECs and prevented Evans blue dye leakage in the VEGF-induced Miles assay in athymic Balb/c nude mice. BET inhibition with JQ1 or shRNA for Brd2 or Brd4 suppressed VEGF-induced migration, proliferation, and stress fiber formation of HUVECs. Furthermore, BET inhibition suppressed phosphorylation of VEGFR2 and PAK1, as well as eNOS activation in VEGF-stimulated HUVECs. Inhibition with VEGFR2 and PAK1 also reduced migration and proliferation, and attenuated the VEGF-induced decrease in TEER. Thus, our observations suggest the important role of BET bromodomain in regulating VEGF-induced angiogenesis. Strategies that target the BET bromodomain may provide a new therapeutic approach for angiogenesis-related diseases.

Clinical Features and Associated Factors of Abdominal Pain in Systemic Lupus Erythematosus

Objective. To evaluate the clinical characteristics of systemic lupus erythematosus (SLE)-induced abdominal pain in a cohort in South China and identify the risk factors for SLE-induced abdominal pain. Methods. This is a retrospective cohort study of SLE patients with complaint of abdominal pain admitted to the first affiliated university hospital of Sun Yat-sen University between 2002 and 2011. Demographic information, clinical features, laboratory findings, SLE Disease Activity Index, and imaging characteristics were documented. Results. Of the 3823 SLE patients reviewed, 213 patients complained of abdominal pain and 132 cases were considered SLE-induced. The most common causes were lupus mesenteric vasculitis (LMV; 73.5%, 97/132) and lupus pancreatitis (LP; 17.4%, 23/132). Other causes included appendicitis, acute gastroenteritis, and peritonitis. Univariate and multivariate logistic regression analysis indicated the European Consensus Lupus Activity Measurement (ECLAM) score was significantly associated with lupus-induced abdominal pain (OR = 1.858, 95% CI: 1.441–2.394, p < 0.001), LMV (OR = 1.713, 95% CI: 1.308-2.244, p < 0.001), and LP (OR = 2.153, 95% CI: 1.282, 3.617, p = 0.004). The serum D-dimer level (OR = 1.004, 95% CI: 1.002-1.005, p < 0.001) was a strongly associated factor for lupus-induced abdominal pain. Moderate and large amounts of ascetic fluid was significantly associated with lupus-induced abdominal pain and LMV. Elevated liver enzymes was a risk factor for LP (OR = 34.605, 95% CI: 3.591-333.472, p = 0.002). Conclusion. LMV and LP were the leading causes of SLE-induced abdominal pain. The serum D-dimer was a strongly associated factor for lupus-induced abdominal pain. ECLAM score was a reliable index in assessment of SLE-associated abdominal pain. Elevated liver enzymes, and moderate or large amounts of ascites, were positively associated with lupus-induced abdominal pain.

Inhibition of 6‐phosphofructo‐2‐kinase suppresses fibroblast‐like synoviocytes‐mediated synovial inflammation and joint destruction in rheumatoid arthritis

Abnormal glycolytic metabolism contributes to joint inflammation in rheumatoid arthritis (RA). The aims of this study were to investigate the role of 6‐phosphofructo‐2‐kinase/fructose‐2,6‐bisphosphatase 3 (PFKFB3), a bifunctional enzyme that controls the glycolytic rate, in regulating fibroblast‐like synoviocyte (FLS)‐mediated synovial inflammation and invasiveness in 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.

Niclosamide induces apoptosis in human rheumatoid arthritis fibroblast-like synoviocytes.

To explore the effects of niclosamide on the viability and apoptosis of rheumatoid arthritis of fibroblast-like synoviocytes (rheumatoid arthritis (RA)fibroblast-like synoviocytes (FLS)), FLS obtained from RA patients were treated with niclosamide. Niclosamide significantly inhibited the viability of RA FLS in a concentration-dependent manner. Niclosamide treated FLS showed a significant increase in the percentage of apoptosis and higher intracellular ROS levels. N-acetyl-l-cysteine (NAC) pretreatment significantly attenuated niclosamide-induced apoptosis. The apoptotic response was due to the up-regulation of pro-apoptotic protein, Bax, and down-regulation of antiapoptotic protein, B cell lymphoma 2 (Bcl-2). The activation of mitochondrial pathway in niclosamide-treated RA FLS induced the cytochrome C, cleavage of caspase-9 and caspase-3. Additionally, niclosamide inhibited the phosphorylation of Akt. Collectively, our results reveal that niclosamide inhibits cell proliferation and induces mitochondrial apoptosis of RAFLSs, which is associated with the modulation of Akt signaling pathways.

The suppression of bromodomain and extra‐terminal domain inhibits vascular inflammation by blocking NF‐κB and MAPK activation

There is increasing evidence indicating that bromodomain and extra‐terminal domain (BET) proteins play a critical role in the regulation of immune and inflammatory responses; however, their contribution to vascular inflammation has not yet been elucidated. In this study, we investigated the effect of inhibiting BET bromodomain on vascular inflammation and the underlying mechanisms.

Triptolide inhibits the migration and invasion of rheumatoid fibroblast-like synoviocytes by blocking the activation of the JNK MAPK pathway

Triptolide, a primary active ingredient extracted from a traditional Chinese herb, Tripterygium wilfordii Hook F, has been demonstrated to have a positive therapeutic effect on patients with rheumatoid arthritis (RA); however, its mechanism of action against RA is not well established. Therefore, in the present study, we observed the effect of triptolide on the aggressive behavior of RA fibroblast-like synoviocytes (RA FLSs), and we explored its underlying signal mechanisms. We found that triptolide treatment significantly reduced the migratory and invasive capacities of RA FLSs in vitro. We also demonstrated that the invasion of RA FLSs into the cartilage, evaluated in the severe combined immunodeficiency (SCID) mouse co-implantation model, was attenuated by treatment with triptolide in vivo. Additionally, the immunofluorescence results showed that triptolide treatment decreased the polymerization of F-actin and the activation of matrix metalloproteinase 9 (MMP-9). To gain insight into the molecular signal mechanisms, we determined the effect of triptolide on the activation of MAPK signal pathways. Our results indicate that triptolide treatment reduced the TNF-α-induced expression of phosphorylated JNK, but did not affect the expression of phosphorylated p38 and ERK. A JNK-specific inhibitor decreased the migration of RA FLSs. We also observed that triptolide administration improved clinical arthritic conditions and joint destruction in mice with collagen-induced arthritis (CIA). Thus, our findings suggest that the therapeutic effects of triptolide on RA might be, in part, due to its contribution to the aggressive behavior of RA FLSs.