Rheumatoid Arthritis: Xu H

Dai SM, Shan ZZ, Xu H, Nishioka K. · Department of Rheumatology and Immunology, Changhai Hospital, Second Military Medical University, 174 Changhai Road, Shanghai 200433, P R China. · Ann Rheum Dis. · Pubmed #17502360 No free full text.

Abstract: Recent data are presented which indicate a critical role for interleukin (IL)-18 in rheumatoid arthritis (RA). The T cells and macrophages invading the synovium or in the synovial fluid are the chief cellular targets of IL-18 in RA. Neutrophils, dendritic cells and endothelial cells may also be cellular mediators of IL-18. The direct effect of IL-18 on fibroblast-like synoviocytes or chondrocytes may not be essential or important. In RA, IL-18, which is mainly produced by macrophages, activates T cells and macrophages to produce proinflammatory cytokines, chemokines, adhesion molecules and RANKL which, in turn, perpetuate chronic inflammation and induce bone and cartilage destruction.

He Y, Xu H, Liang L, Zhan Z, Yang X, Yu X, Ye Y, Sun L. · First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China. · Arthritis Rheum. · Pubmed #18975348 No free full text.

Abstract: 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.

Xu L, Pan J, Chen Q, Yu Q, Chen H, Xu H, Qiu Y, Yang X. · College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China. · Food Chem Toxicol. · Pubmed #18952137 No free full text.

Abstract: Triptolide (TP) is a major active component of Tripterygium wilfordii Hook F (TWHF), which is used to treat rheumatoid arthritis (RA). TP has a narrow therapeutic window. To increase the therapeutic index of TP, a novel TP-loaded transdermal delivery system, named TP-loaded hydrogel-thickened microemulsion (TP-MTH), has been developed to treat RA. Our previous studies have demonstrated the good efficacy of TP-MTH in animals. This paper evaluated the safety of TP-MTH with several animals. Results demonstrated no obvious toxicities in a series of toxicity tests: acute toxicity study of TP-MTH (1.2mg/kg) in rabbits, 6-month long-term toxicity study of TP-MTH (0.06, 0.18, 0.54mg/kg) in rabbits, safety pharmacology study of TP-MTH (0.03, 0.09, 0.27mg/kg, for 5 d) in mice and beagle dogs, skin irritation study in rabbits, and skin allergic reaction test in guinea pigs. Only mild reversible skin irritation signs were observed on the skin of animals. These studies suggest that topical TP-MTH is a promising drug formulation for the treatment of RA.

Gao Q, Shan J, Di L, Jiang L, Xu H. · Department of Pharmacology, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210029, China. · J Ethnopharmacol. · Pubmed #18835428 No free full text.

Abstract: AIM OF THIS STUDY: Daphnetin was regarded as the mark compound for quality control of Zushima-Pian, a traditional Chinese medicine tablet for treating rheumatoid arthritis (RA). However, no in vivo study on the therapeutic effects of daphnetin for RA has been reported. MATERIALS AND METHODS: The adjuvant arthritic (AA) rat model was developed to evaluate the anti-arthritic effects of daphnetin. After immunized with Freund's complete adjuvant (FCA), the rats were treated with daphnetin (2.25 and 4.5mg/kg) for three weeks. We determined the change of secondary paw swelling and the arthritis scores of these tested rats. The severity of arthritis in the knee joints was evaluated by histological assessment of cartilage destruction. The levels of IL-1, TNF-alpha and MIF in the serum were measured by ELISA. RESULTS AND CONCLUSIONS: Our results showed that daphnetin significantly reduced paw swelling and decreased the arthritis scores. The pathological examination demonstrated that articular cartilage degeneration with synovial hyperplasia and inflammatory cells infiltration in AA rats were suppressed by daphnetin. There was significant reduction in production of interleukin-1 (IL-1), tumor necrosis factor (TNF-alpha) and macrophage migration inhibitory factor (MIF) in serum of AA rats treated with daphnetin except the low dose group (2.25mg/kg) on TNF-alpha. In conclusion, we demonstrates that daphnetin is highly effective on preventing and suppressing the development and progression of adjuvant-induced arthritis and provides direct evidences that daphnetin is one of the active principle of Zushima-Pian for treating rheumatoid arthritis.

Lo CK, Lam QL, Sun L, Wang S, Ko KH, Xu H, Wu CY, Zheng BJ, Lu L. · Department of Pathology, Center of Infection and Immunology, University of Hong Kong, Hong Kong, China. · Arthritis Rheum. · Pubmed #18759269 No free full text.

Abstract: OBJECTIVE: An altered phenotype and dysfunction of natural killer (NK) cells have been observed in patients with rheumatoid arthritis. The aim of this study was to determine whether dysregulated NK cells contribute to the pathogenesis of experimental arthritis. METHODS: For initiation of collagen-induced arthritis (CIA), DBA/1J mice were immunized with type II collagen in Freund's adjuvant. Control mice were immunized with adjuvant alone. NK cells from the blood, spleens, and bone marrow of immunized mice were analyzed by flow cytometry. Levels of interleukin-17 (IL-17) secretion and autoantibody production were measured by enzyme-linked immunosorbent assays. Immunized mice in which NK cells were depleted by anti-asialo G(M1) antibody treatment were assessed for the development of CIA. Moreover, sorting-purified NK cells from both mice with CIA and control mice were analyzed for cytokine gene expression. RESULTS: We observed markedly reduced frequencies of NK cells in the blood and spleens of mice with CIA compared with the frequencies in adjuvant-treated control mice. Upon NK cell depletion, immunized mice displayed an early onset of arthritis with more severe clinical symptoms, which correlated with increased plasma cell generation and autoantibody production. Moreover, a substantially increased number of IL-17-secreting cells in synovial tissue and more pronounced joint damage were observed. Freshly isolated NK cells from mice with CIA showed markedly reduced expression of interferon-gamma (IFNgamma). Furthermore, coculture of normal NK cells and CD4+ T cells revealed that NK cells strongly suppressed production of Th17 cells via their IFNgamma production. CONCLUSION: These results suggest that NK cells play a protective role in the development of experimental arthritis, an effect that is possibly mediated by suppressing Th17 cell generation via IFNgamma production.

Fan K, Dai J, Wang H, Wei H, Cao Z, Hou S, Qian W, Wang H, Li B, Zhao J, Xu H, Yang C, Guo Y. · Second Military Medical University, Shanghai, China. · Arthritis Rheum. · Pubmed #18576331 links to  free full text

Abstract: OBJECTIVE: To test the effects of a novel monoclonal antibody (mAb) against human osteopontin (OPN) in the prevention and treatment of collagen-induced arthritis (CIA) and to elucidate the underlying mechanisms of these effects. METHODS: DBA/1J mice immunized with type II collagen to induce CIA were monitored to assess the effects of anti-OPN mAb on the clinical severity of the disease, and pathologic changes in the joints were examined histologically. The effects of anti-OPN mAb on survival of activated T cells from arthritic mice and from the synovial fluid of patients with rheumatoid arthritis (RA) were determined by TUNEL assay or annexin V assay. The levels of apoptosis-related proteins (Bim, Bax, and Bcl-2) and NF-kappaB were detected by immunoblot analysis. RESULTS: One anti-OPN mAb, 23C3, was effective in inhibiting the development of CIA and even reversing established disease in DBA/1J mice. Monoclonal antibody 23C3 reduced the levels of serum type II collagen-specific autoantibodies and proinflammatory cytokines, and suppressed T cell recall responses to type II collagen. Mechanistic studies demonstrated that OPN prevented the death of type II collagen-activated murine T cells and synovial T cells from RA patients. Monoclonal antibody 23C3 promoted apoptosis of the activated T cells, particularly CD4+ T cells, by inhibiting activation of NF-kappaB and by altering the balance among the proapoptotic proteins Bim and Bax and the antiapoptotic protein Bcl-2. Screening of a phage display peptide library led to identification of the epitope ATWLNPDPSQKQ as being recognized by this novel antibody. CONCLUSION: Because of its ability to effectively promote apoptosis of activated T cells, mAb 23C3 may be a novel therapeutic agent for the treatment of RA.

Xu H, George V. · Department of Biostatistics, Medical College of Georgia, 1120 15th Street, AE-3031, Augusta, Georgia 30912, USA. · BMC Proc. · Pubmed #18466530 links to  free full text

Abstract: ABSTRACT : Family-based association approaches such as the transmission-disequilibrium test (TDT) are used extensively in the study of genetic traits because they are generally robust to the presence of population structure. However, these approaches necessarily involve recruitment of families, which is more costly and time-consuming than sampling unrelated individuals in the population-based approaches. Therefore, a family-based approach, which has high power, would be appealing because of the gain in time and cost due to the reduced sample size that is required to attain adequate power. Here we introduce a new family-based transmission test using the joint transmission status from affected sib pairs. We show that by including the transmission status of both siblings, our method gives higher power than the TDT design, while maintaining the correct type I error rate. We use the simulated data from affected sib-pair families with rheumatoid arthritis provided by Genetic Analysis Workshop 15 to illustrate our approach.

Xu H, He Y, Yang X, Liang L, Zhan Z, Ye Y, Yang X, Lian F, Sun L. · Department of Rheumatology, The First Affiliated Hospital, SUN Yat-sen University, Guangzhou, Guangdong 510080, PR China. · Rheumatology (Oxford). · Pubmed #17314215 links to  free full text

Abstract: OBJECTIVES: Recent studies indicate that the anti-malarial agent artemisinin and its derivatives may exert an anti-inflammatory effect. In this study, we explored the effect of artesunate, an artemisinin derivative, on tumour necrosis factor (TNF)-alpha-induced production of interleukins, IL-1beta, IL-6 and IL-8, in human rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS), and further investigated the signal mechanism by which this compound modulates those cytokines' production. METHODS: RA FLS obtained from patients with active RA were stimulated with TNF-alpha and incubated with artesunate, and IL-1beta, IL-6 and IL-8 production was measured by ELISA. DNA-binding activity and nuclear translocation of nuclear factor kappa B (NF-kappaB) were measured by a sensitive multi-well colourimetric assay and confocal fluorescence microscopy, respectively. Signal transduction proteins expression was measured by western blot. RESULTS: Artesunate decreased the secretion of IL-1beta, IL-6 and IL-8 from TNF-alpha-stimulated RA FLS in a dose-dependent manner. Artesunate also prevented TNF-alpha-induced nuclear NF-kappaB translocation, DNA-binding activity and gene transcriptional activity, as well as phosphorylation and degradation of IkappaBalpha, but phosphorylation of p38 mitogen-activated protein kinase, extracellular signal-regulated kinase and c-Jun N-terminal kinase were unaffected. The production of IL-1beta, IL-6 and IL-8 induced by TNF-alpha was decreased by pyrrolidine dithiocarbamate (PDTC), a chemical inhibitor of NF-kappaB. These observations suggest that artesunate inhibits production of IL-1beta, IL-6 and IL-8 through inhibition of NF-kappaB signalling pathway. We also showed that artesunate prevented Akt phosphorylation. TNF-alpha-induced production of IL-1beta, IL-6 and IL-8 was hampered by treatment with the phosphatidylinositol 3 (PI3) kinase inhibitor LY294002, suggesting that inhibition of Akt activation might inhibit IL-1beta, IL-6 and IL-8 production induced by TNF-alpha. CONCLUSIONS: Our results indicate that artesunate exerts an anti-inflammatory effect in RA FLS and provide the evidence that artesunate may have therapeutic potential for RA.

Xu H, Liu P, Liang L, Danesh FR, Yang X, Ye Y, Zhan Z, Yu X, Peng H, Sun L. · Department of Rheumatology, First Affiliated Hospital, Sun Yat-sen University, No. 58 Zhongshan Road 2, Guangzhou, Guangdong 510080, Peoples Republic of China. · Arthritis Rheum. · Pubmed #17075836 links to  free full text

Abstract: OBJECTIVE: Increasing evidence indicates that RhoA may play a central role in the inflammatory response. This study was conducted to examine the role of RhoA in mediating the activation of NF-kappaB in tumor necrosis factor alpha (TNFalpha)-stimulated rheumatoid synoviocytes, and to evaluate the modulatory effects of statins on the TNFalpha-induced activation of RhoA and NF-kappaB and the secretion of proinflammatory cytokines by rheumatoid synoviocytes. METHODS: Rheumatoid synoviocytes obtained from patients with active rheumatoid arthritis were stimulated with TNFalpha and incubated with simvastatin (SMV) (1 muM). RhoA activity was assessed by a pull-down assay. NF-kappaB DNA binding activity and nuclear translocation of NF-kappaB were measured by a sensitive multiwell colorimetric assay and confocal fluorescence microscopy, respectively. RESULTS: TNFalpha stimulation elicited a robust increase in RhoA activity in a dose-dependent manner, and SMV mitigated this increase. TNFalpha also hastened NF-kappaB nuclear translocation of subunit p65 and increased DNA binding activity, luciferase reporter gene expression, degradation of IkappaB, and secretion of interleukin-1beta (IL-1beta) and IL-6. SMV prevented the increase in NF-kappaB activation and rise in IL-1beta and IL-6 levels induced by TNFalpha, whereas mevalonate and geranylgeranyl pyrophosphate reversed the inhibitory effects of SMV on activation of NF-kappaB and RhoA. Furthermore, cotransfection with a dominant-negative mutant of RhoA demonstrated that the TNFalpha-induced signaling pathway involved sequential activation of RhoA, leading to NF-kappaB activation and, ultimately, to secretion of cytokines. CONCLUSION: This study identifies RhoA as the key regulator of TNFalpha-induced NF-kappaB activation, which ultimately results in the secretion of proinflammatory cytokines in rheumatoid synoviocytes. The findings provide a new rationale for the antiinflammatory effects of statins in inflammatory arthritis.

Xu H, Edwards J, Banerji S, Prevo R, Jackson DG, Athanasou NA. · Department of Orthopaedics, Xijing Hospital, Fourth Military Medical University, Xian, 710032, People's Republic of China. · Ann Rheum Dis. · Pubmed #14644866 links to  free full text

Abstract: OBJECTIVES: To investigate the distribution of lymphatic vessels in normal, rheumatoid arthritis (RA) and osteoarthritis (OA) synovium. METHODS: Synovial tissues from 5 normal controls, 14 patients with RA, and 16 patients with OA were studied. Lymphatic vessels were identified by immunohistochemistry using antibodies directed against the lymphatic endothelial hyaluronan receptor (LYVE-1) and recognised blood vessel endothelial markers (factor VIII, CD34, CD31). RESULTS: Lymphatic vessels were found in all zones of the normal, OA, and RA synovial membrane. Few lymphatic vessels were seen in the sublining zone in normal and OA synovium which did not show villous hypertrophy. However, in both RA synovium and OA synovium showing villous hypertrophy and a chronic inflammatory cell infiltrate, numerous lymphatic vessels were seen in all zones of the synovial membrane, including the sublining zone of the superficial subintima. CONCLUSIONS: Lymphatic vessels are present in normal and arthritic synovial tissues and are more numerous and prominent where there is oedema and an increase in inflammatory cells in the subintima, particularly in RA. This may reflect increased transport of hyaluronan and leucocyte trafficking in inflamed synovial tissues.