Zhongping Zhan

Antiinflammatory effect of Rho kinase blockade via inhibition of NF‐κB activation in rheumatoid arthritis

OBJECTIVE There is increasing evidence that the RhoA signaling pathway may play a critical role in the inflammatory response. This study was undertaken to examine the effects of RhoA and its downstream effector Rho kinase (ROK) in synovial inflammation in rheumatoid arthritis (RA). METHODS RhoA activity was assessed by pull-down assay. Fasudil and Y27632, both specific inhibitors of ROK, were used to examine the role of ROK in inflammatory responses in vivo and in vitro. Nuclear translocation of NF-kappaB was measured by confocal fluorescence microscopy, and DNA binding activity was assessed with a sensitive multiwell colorimetric assay. Enzyme-linked immunosorbent assay was used to detect cytokine production. RESULTS Increased activation of RhoA was found in inflamed synovial membrane cells isolated from patients with RA and from rats with collagen-induced arthritis (CIA). Intraperitoneal administration of fasudil in rats with CIA significantly reduced synovial inflammation and ROK activity. In vitro, treatment with fasudil or Y27632 decreased production of tumor necrosis factor alpha (TNFalpha), interleukin-1beta (IL-1beta), and IL-6 by synovial membrane cells, peripheral blood mononuclear cells, and fibroblast-like synoviocytes from patients with active RA. Inhibition of ROK by specific inhibitors or ROK small interfering RNA suppressed lipopolysaccharide- or TNFalpha-induced NF-kappaB nuclear translocation, DNA binding activity, luciferase reporter gene expression, and IkappaBalpha degradation. CONCLUSION The results of this study provide new evidence that blockade of ROK inhibits activation of NF-kappaB and production of proinflammatory cytokines, suggesting a critical role of ROK in the synovial inflammation of RA. Specific inhibition of ROK may be a novel therapeutic approach in RA.

The anti-malaria agent artesunate inhibits expression of vascular endothelial growth factor and hypoxia-inducible factor-1α in human rheumatoid arthritis fibroblast-like synoviocyte

Increasing evidence indicates that the anti-malarial agent artemisinin and its derivatives may exert anti-angiogenic effect. In the present study, we explored the effect of artesunate, a artemisinin derivative, on TNFα- and hypoxia-induced expression of hypoxia inducible factor-1α (HIF-1α) and secretion of vascular endothelial growth factor (VEGF) and inteleukin-8 (IL-8) in human rheumatoid arthritis fibroblast-like synoviocytes (RA FLS), and further investigated the signal mechanism by which this compound modulates HIF-1α, VEGF and IL-8 expression. RA FLS obtained from patients with active rheumatoid arthritis were pretreated with artesunate, and then stimulated with TNFα and hypoxia. Production of VEGF and IL-8 was measured by ELISA. Nuclear location of HIF-1α was measured by confocal fluorescence microscopy. HIF-1α and other signal transduction proteins expression was measured by Western blot. Artesunate decreased the secretion of VEGF and IL-8 from TNFα- or hypoxia-stimulated RA FLS in a dose-dependent manner. Artesunate also inhibited TNFα- or hypoxia-induced nuclear expression and translocation of HIF-1α. We also showed that artesunate prevented Akt phosphorylation, but did not find evidence that phosphorylation of p38 and ERK was affected. TNFα- or hypoxia-induced secretion of VEGF and IL-8 and expression of HIF-1α were hampered by treatment with the PI3 kinase inhibitor LY294002, suggesting that inhibition of PI3 kinase/Akt activation might inhibit VEGF and IL-8 secretion and HIF-1α expression induced by TNFα or hypoxia. Our results suggest that artesunate inhibits angiogenic factor expression in RA FLS, and provide novel evidence that, as a low-cost agent, artesunate may have therapeutic potential for RA.

Clinical features and independent predictors of pulmonary arterial hypertension in systemic lupus erythematosus

Pulmonary arterial hypertension (PAH) is a devastating complication of systemic lupus erythematosus (SLE). We aim to estimate the putative predictors contributing to early identification of PAH, thus improve appropriate medical intervention and a better prognosis. A retrospective case–control study was conducted. Forty-one SLE patients with PAH and 106 SLE patients without PAH were enrolled. Demographic variables, clinical features, and laboratory data were compared between the two groups. Univariate and multivariate logistic regression models were used to examine the predictors contributing to PAH in SLE. Serositis, Raynaud’s phenomenon, high disease activity, anticardiolipin antibodies, and anti-U1RNP were significantly associated with SLE-PAH. Univariate and multivariate analysis showed that Raynaud’s phenomenon, anticardiolipin antibodies, and anti-U1RNP were independent predictors of PAH in SLE. This study highlighted the clinical pattern of SLE-PAH patients, and underlined the leading predictors of PAH development among patients with SLE. Routine echocardiography is recommended in SLE patients with the independent predictors mentioned above.

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.

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-1β 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-1β-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.

Systemic-Lupus-Erythematosus-Related Acute Pancreatitis: A Cohort from South China

Acute pancreatitis (AP) is a rare but life-threatening complication of SLE. The current study evaluated the clinical characteristics and risk factors for the mortality of patients with SLE-related AP in a cohort of South China. Methods. Inpatient medical records of SLE-related AP were retrospectively reviewed. Results. 27 out of 4053 SLE patients were diagnosed as SLE-related AP, with an overall prevalence of 0.67%, annual incidence of 0.56‰ and mortality of 37.04%. SLE patients with AP presented with higher SLEDAI score (21.70 ± 10.32 versus 16.17 ± 7.51, P = 0.03), more organ systems involvement (5.70 ± 1.56 versus 3.96 ± 1.15, P = 0.001), and higher mortality (37.04% versus 0, P = 0.001), compared to patients without AP. Severe AP (SAP) patients had a significant higher mortality rate compared to mild AP (MAP) (75% versus 21.05%, P = 0.014). 16 SLE-related AP patients received intensive GC treatment, 75% of them exhibited favorable prognosis. Conclusion. SLE-related AP is rare but concomitant with high mortality in South Chinese people, especially in those SAP patients. Activity of SLE, multiple-organ systems involvement may attribute to the severity and mortality of AP. Appropriate glucocorticosteroid (GC) treatment leads to better prognosis in majority of SLE patients with AP.

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-1β 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.

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.

Increased phosphorylation of ezrin/radixin/moesin proteins contributes to proliferation of rheumatoid fibroblast-like synoviocytes

OBJECTIVES Increasing evidence indicates that ezrin/radixin/moesin (ERM) proteins may play a critical role in cell proliferation. This study examined the role of ERM proteins in proliferation of fibroblast-like synoviocytes (FLS) from patients with RA. METHODS Synovial tissues (STs) were obtained from 18 RA and 6 OA patients. The expression of ERM and its phosphorylated proteins in cultured FLS and ST was assessed by western blots or IF staining. Small interference RNA (siRNA)-mediated ERM knockdown was used to inhibit phosphorylation of ERM. Proliferation of FLS was measured by bromodeoxyuridine (BrdU) incorporation into cell DNA and by PCNA immunoblotting. RESULTS Our study showed that increased phosphorylation of ERM proteins was found in ST and FLS from patients with RA as compared with OA patients and non-arthritis controls. Treatment with TNF-α, IL-1β or PDGF-induced phosphorylation of ERM proteins in dose- and time-dependent manner by RA FLS, but did not affect the expression of total ERM protein. Rho kinase and p38MAPK signal pathways were involved in TNF-α-induced ERM phosphorylation. We further showed that inhibition of ERM phosphorylation by siRNA-mediated ERM knockdown suppressed TNF-α- or IL-1β-induced BrdU incorporation and PCNA expression in RA FLS. CONCLUSIONS This study provides the novel evidence that increased phosphorylation of ERM proteins may contribute to proliferation of RA FLS, suggesting that specific inhibition of ERM phosphorylation may be a new therapeutic approach for RA.

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.