Arthritis research & therapy (ARTHRITIS RES THER)

Publications in this journal

• Article: Porphyromonas gingivalis and the pathogenesis of rheumatoid arthritis: analysis of various compartments including the synovial tissue

  Michele C Totaro, Paola Cattani, Francesco Ria, Barbara Tolusso, Elisa Gremese, Anna L Fedele, Sara D'Onghia, Simona Marchetti, Di Sante G, Silvia Canestri, Gianfranco Ferraccioli
  Arthritis research & therapy 06/2013;
• Article: A novel in vitro bovine cartilage punch model for assessing the regeneration of focal cartilage defects with biocompatible bacterial nanocellulose.

  David Pretzel, Stefanie Linss, Hannes Ahrem, Michaela Endres, Christian Kaps, Dieter Klemm, Raimund W Kinne
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  ABSTRACT: INTRODUCTION: Current therapies for articular cartilage defects fail to achieve qualitatively sufficient tissue regeneration, possibly because of a mismatch between the speed of cartilage rebuilding and the resorption of degradable implant polymers. The present study focused on the self-healing capacity of resident cartilage cells in conjunction with cell-free and biocompatible (but non-resorbable) bacterial nanocellulose (BNC). This was tested in a novel in vitro bovine cartilage punch model. METHODS: Standardized bovine cartilage discs with a central defect filled with BNC were cultured for up to 8 weeks with/without stimulation with TGF-beta1. Cartilage formation and integrity were analyzed by histology, immunohistochemistry, and electron microscopy. Content, release, and neosynthesis of the matrix molecules proteoglycan/aggrecan, collagen II, and collagen I were also quantified. Finally, gene expression of these molecules was profiled in resident chondrocytes and chondrocytes migrated onto the cartilage surface or the implant material. RESULTS: Non-stimulated and especially TGF-beta1-stimulated cartilage discs displayed a preserved structural and functional integrity of the chondrocytes and surrounding matrix, remained vital in long-term culture (8 weeks) without signs of degeneration, and showed substantial synthesis of cartilage-specific molecules at the protein and mRNA level. Whereas mobilization of chondrocytes from the matrix onto the surface of cartilage and implant was pivotal for successful seeding of cell-free BNC, chondrocytes did not immigrate into the central BNC area, possibly due to the relatively small diameter of its pores (2-5 um). Chondrocytes on the BNC surface showed signs of successful redifferentiation over time, including increase of aggrecan/collagen type II mRNA, decrease of collagen type I mRNA, and initial deposition of proteoglycan and collagen type II in long-term high-density pellet cultures. Although TGF-beta1 stimulation showed protective effects on matrix integrity, effects on other parameters were limited. CONCLUSIONS: The present bovine cartilage punch model represents a robust, reproducible, and highly suitable tool for the long-term culture of cartilage, maintaining matrix integrity and homoeostasis. As an alternative to animal studies, this model may closely reflect early stages of cartilage regeneration, allowing the evaluation of promising biomaterials with/without chondrogenic factors.
  Arthritis research & therapy 05/2013; 15(3):R59.
• Article: Adenosine A2A receptors promote collagen production by a Fli1- and CTGF-mediated mechanism.

  Edwin Sl Chan, Hailing Liu, Patricia Fernandez, Alex Luna, Miguel Perez-Aso, Andreea M Bujor, Maria Trojanowska, Bruce N Cronstein
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  ABSTRACT: INTRODUCTION: Adenosine, acting through the A2A receptor, promotes tissue matrix production in the skin and the liver and induces the development of dermal fibrosis and cirrhosis in murine models. Since expression of A2A receptors is increased in scleroderma fibroblasts, we examined the mechanisms by which the A2A receptor produces its fibrogenic effects. METHODS: The effects of A2A receptor ligation on the expression of the transcription factor, Fli1, a constitutive repressor for the synthesis of matrix proteins, such as collagen, is studied in dermal fibroblasts. Fli1 is also known to repress the transcription of CTGF/CCN2, and the effects of A2A receptor stimulation on CTGF and TGF-beta1 expression are also examined. RESULTS: A2A receptor occupancy suppresses the expression of Fli1 by dermal fibroblasts. A2A receptor activation induces the secretion of CTGF by dermal fibroblasts, and neutralization of CTGF abrogates the A2A receptor-mediated enhancement of collagen type I production. A2AR activation, however, resulted in a decrease in TGF-beta1 protein release. CONCLUSIONS: Our results suggest that Fli1 and CTGF are important mediators of the fibrogenic actions of adenosine and the use of small molecules such as adenosine A2A receptor antagonists may be useful in the therapy of dermal fibrosis in diseases such as scleroderma.
  Arthritis research & therapy 05/2013; 15(3):R58.
• Article: Correction: TNF/TNFR signal transduction pathway-mediated anti-apoptosis and anti-inflammatory effects of sodium ferulate on IL-1β- induced rat osteoarthritis chondrocytes in vitro.

  Jun Qin, Liang Shang, An-Song Ping, Jing Li, Xiao-Jun Li, Hong Yu, Jacques Magdalou, Liao-Bin Chen, Hui Wang
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  ABSTRACT: INTRODUCTION: Sodium ferulate (SF) is a natural component of traditional Chinese herbs. Our previous study shows that SF has a protective effect on osteoarthritis (OA). The objective of this study was to investigate the effect of SF on TNF/TNFR signal transduction pathway of rat OA chondrocytes. METHODS: Primary rat articular chondrocytes were co-treated with interleukin 1 beta (IL-1beta) and SF. Chondrocytes apoptosis was assessed by fluorescein isothiocyanate-Annexin V/propidium iodide assay. The PCR Array was used to screen the expression of 84 key genes involved in apoptosis. The release of tumor necrosis factor-alpha (TNF-alpha) and prostaglandin E2 (PGE2) were analyzed by enzyme linked immunosorbent assay. Expressions of proteins were assessed by Western blotting. The activity of nuclear factor-kappaB was determined by electrophoretic mobility shift assay (EMSA). Gene expression of inducible nitric oxide synthase (iNOS) was evaluated by real-time quantitative PCR. Nitric oxide (NO) content was measured with Griess method. RESULTS: After treatment with SF, apoptosis rate of chondrocytes significantly attenuated (P<0.01). The result of Apoptosis PCR Array suggested that mRNA expression of some core proteins in TNF/TNFR pathway showed valuable regulation. The protein expressions of TNF-alpha, tumor necrosis factor receptor-1 (TNFR-1), TNF receptor-associated death domain (TRADD), caspase-8 and caspase-3 were prevented by SF in the concentration-dependent manner. SF also inhibited activities of caspase-8 and caspase-3 compared with OA model control (P<0.01). TNF receptor-associated factor 2 (TRAF-2) expression, phosphorylations of inhibitor of nuclear factor kappa-B kinase subunit alpha (IKKalpha), inhibitor of nuclear factor kappa-B kinase subunit beta (IKKbeta) and nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IkappaBalpha) were all concentration-dependently suppressed by SF treatment. The result of EMSA showed that SF inhibited the activity of nuclear factor-kappaB. In addition, the expressions of cycloxygenase 2 and iNOS, and the contents of PGE2 and NO were attenuated with the treatment of SF (P<0.01). CONCLUSIONS: SF has anti-apoptosis and anti-inflammatory effects on OA model induced by IL-1beta in vitro, which were due to the inhibitory actions on caspase-dependent apoptosis pathway and IKK/NF-kappaB signal transduction pathway of TNF/TNFR pathway.
  Arthritis research & therapy 05/2013; 15(3):407.
• Article: A complicated liaison: IL-33 and IL-33R in arthritis pathogenesis.

  Thomas Kamradt, Sebastian Drube
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  ABSTRACT: Interruption of cytokine signaling, by targeting either the cytokine itself or its cellular receptor, is a mainstay in the therapy for patients with rheumatic diseases. Interleukin (IL)-33, a member of the IL-1 cytokine family, has emerged as an important mediator of inflammatory responses. In a side-by-side examination of IL-33-deficient and IL-33 receptor (IL-33R)-deficient mice in the K/BxN serum transfer model, arthritis was ameliorated in the IL-33R knockout (KO) mice but not in the IL-33 KO mice. These findings complement previous knowledge on IL-33R signaling, demonstrating that the IL-33R cross-activates other signaling pathways in addition to IL-33-mediated signals. The results reported by Martin and colleagues in a previous issue of Arthritis Research & Therapy underline the clinical relevance of IL-33R cross-signaling and further illustrate that targeting a cytokine receptor (IL-33R) can have completely different clinical outcomes than targeting the respective cytokine.
  Arthritis research & therapy 05/2013; 15(3):115.
• Article: What can rheumatologists learn from translational cancer therapy?

  Jonathan P Sherlock, Andrew D Filer, John D Isaacs, Christopher D Buckley
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  ABSTRACT: It is well established that an intimate connection exists between inflammation and neoplasia. Indeed, particular chronic infections and autoimmune processes giving rise to prolonged site-specific inflammation are known to increase the probability of the development of specific cancers. Molecular characterisation of these processes has revealed profound similarities in the specific molecules involved in persistence of inflammation and in both the primary induction of neoplastic processes and in specification of the preferred anatomic sites of metastatic spread. The therapeutic importance of these findings is underscored by the remarkable success in the treatment of autoimmune pathology using medications initially developed for use in oncology and this arena is one of considerable therapeutic promise for rheumatologists.
  Arthritis research & therapy 05/2013; 15(3):114.
• Article: MMP-2 mediates local degradation and remodeling of collagen by annulus fibrosus cells of the intervertebral disc.

  Anshu Rastogi, Hyunchul Kim, Julianne D Twomey, Adam H Hsieh
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  ABSTRACT: INTRODUCTION: Degeneration of the intervertebral disc (IVD) is characterized by marked degradation and re-structuring of the annulus fibrosus (AF). While several matrix metalloproteinases (MMPs) have been found to be more prevalent in degenerate discs, their coordination and function within the context of the disease process are still not well understood. In this study, we sought to determine whether MMP-2 is associated with degenerative changes in the AF, and to identify the manner by which AF cells utilize MMP-2. METHODS: Two established animal models of disc degeneration, static compression and trans-annular needle puncture of rodent caudal discs, were examined for MMP-2 immunopositivity. Using lentiviral transduction of an shRNA expression cassette we screened and identified an effective shRNA sequence for generating stable RNA interference to silence MMP-2 expression in primary rat AF cells. Gelatin films were used to compare gelatinase activity and spatial patterns of degradation between transduced cells, and both non-infected and nonsense shRNA controls. The functional significance of MMP-2 was determined by assessing the ability for cells to remodel collagen gels. RESULTS: Both static compression and 18g annular puncture of rodent caudal discs stimulated an increase in MMP-2 activity with concurrent lamellar disorganization in the AF, while 22g and 26g needle injuries did not. To investigate the functional role of MMP-2, we established lentivirus-mediated RNAi to induce stable knock down of transcript levels by as much as 88%, and protein levels by as much as 95% over 10 days. Culturing transduced cells on gelatin films confirmed that MMP-2 is the primary functional gelatinase in AF cells, and that MMP-2 is utilized locally in regions immediately around AF cells. In collagen gels, transduced cells demonstrated an inability to remodel collagen matrices. CONCLUSIONS: Our study indicates that increases in MMP-2 observed in human degenerate discs are mirrored in experimentally-induced degenerative changes in rodent animal models. AF cells appear to utilize MMP-2 in a very directed fashion for local matrix degradation and collagen remodeling. This suggests that MMP-2 may have a functionally significant role in the etiology of degenerative disc disease, and could be a potential therapeutic target.
  Arthritis research & therapy 04/2013; 15(2):R57.
• Article: Cigarette smoking and smoking cessation in relation to risk of rheumatoid arthritis in women.

  Daniela Di Giuseppe, Nicola Orsini, Lars Alfredsson, Johan Askling, Alicja Wolk
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  ABSTRACT: INTRODUCTION: Whereas the overall association between smoking and rheumatoid arthritis (RA) must be regarded as established, considerably less is known about how much smoking is needed to increase the risk of RA, that is, the effect of smoking intensity, duration and cessation. METHODS: The Swedish Mammography Cohort, including 34,101 women aged 54 to 89 years, was followed up from January 1, 2003 through December 31, 2010 (219 RA cases identified). Relative risks (RR) and their 95% confidence intervals (CI) were estimated as rate ratios using Cox proportional hazards model. RESULTS: There was a statistically significant association between smoking intensity (RR comparing 1 to 7 cigarettes/day vs never smoking 2.31 (95% CI: 1.59, 3.36)) as well as duration of smoking (comparing 1 to 25 years vs never smoking RR = 1.60 (95% CI: 1.07, 2.38)) and risk of RA. Compared to never smokers, the risk was still significantly elevated 15 years after smoking cessation (RR = 1.99 (95% CI: 1.23, 3.20)). However, among former smokers, the risk of RA seemed to be decreasing over time since stopping smoking: women who stopped smoking 15 years before the start of the follow-up had 30% lower risk of RA compared to those who stopped only a year before start of the follow-up (RR = 0.70 (95% CI: 0.24,2.02)). CONCLUSIONS: This prospective study highlights that even light cigarette smoking is associated with increased risk of RA in women and that smoking cessation may reduce, though not remove, this risk.
  Arthritis research & therapy 04/2013; 15(2):R56.
• Article: Correlations between angiogenic factors and capillaroscopic patterns in systemic sclerosis.

  Jerome Avouac, Maeva Vallucci, Vanessa Smith, Patricia Senet, Barbara Ruiz, Alberto Sulli, Carmen Pizzorni, Camille Frances, Gilles Chiocchia, Maurizio Cutolo, Yannick Allanore
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  ABSTRACT: INTRODUCTION: To assess whether nailfold videocapillaroscopy (NVC) patterns are associated with levels of angiogenic factors in systemic sclerosis (SSc). METHODS: Circulating endothelial progenitor cells (EPCs) and circulating endothelial cells (CECs) were measured in the peripheral blood of 60 consecutive SSc patients. Serum levels of eight endothelial markers were first measured in these 60 patients, and then in an independent replication cohort of 43 SSc patients in case of association with NVC patterns. NVC patterns were determined by four independent investigators blinded to vascular markers. RESULTS: Patients with the late NVC pattern exhibited lower EPC levels (p<0.0001) and higher VEGF levels (p=0.03). Higher VEGF levels were confirmed to be associated with the late NVC pattern in the replication cohort (p=0.01). By multivariate analysis focused on biomarkers, lower EPC (p=0.03) and higher VEGF levels (p=0.001) were independently associated with the late NVC pattern. In an alternate multivariate model including these 2 factors and SSc-related disease characteristics, lower EPC counts (p=0.005), higher VEGF levels (p=0.01), history of digital ulcers (p=0.04) and a modified Rodnan skin score >14 (p<0.0001), were independently associated with the late NVC pattern. CONCLUSION: Our data revealed decreased EPC counts and increased VEGF levels in patients with the late NVC pattern. Further studies are now needed to determine the role of VEGF and EPCs in endothelial injury and repair in SSc.
  Arthritis research & therapy 04/2013; 15(2):R55.
• Article: Shear stress modulates macrophage-induced urokinase plasminogen activator expression in human chondrocytes.

  Chih-Chang Yeh, Shun-Fu Chang, Ting-Ying Huang, Hsin-I Chang, Hsing-Chun Kuo, Yi-Chien Wu, Ching-Hsiang Hsieh, Chung-Sheng Shi, Cheng-Nan Chen
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  ABSTRACT: INTRODUCTION: Synovial macrophages, which can release proinflammatory factors, are responsible for the up-regulation of cartilage breakdown proteases, and play critical roles in cartilage degradation during the progression of osteoarthritis (OA). In addition, shear stress exerts multifunctional effects on chondrocytes by inducing the synthesis of catabolic or anabolic genes. However, the interplay of macrophages, chondrocytes and shear stress during the regulation of cartilage function remains poorly understood. We investigated the mechanisms underlying the modulation of human chondrocyte urokinase plasminogen activator (uPA) expression by macrophages and shear stress. METHODS: Human chondrocytes were stimulated by peripheral blood-macrophage- conditioned medium (PB-MCM), or exposure of chondrocytes cultured in PB-MCM to different levels of shear stress (2-20 dyn/cm2). Real-time polymerase chain reaction was used to analyze uPA gene expression. Inhibitors and small interfering RNA were used to investigate the mechanism for the effects of PB-MCM and shear stress in chondrocytes. RESULTS: Stimulation of human chondrocytes with PB-MCM was found to induce uPA expression. We demonstrate that activation of the JNK and Akt pathways and NF-kappaB are critical for PB-MCM-induced uPA expression. Blocking assays using IL-1ra further demonstrated that IL-1beta in PB-MCM is the major mediator of uPA expression in chondrocytes. PB-MCM-treated chondrocytes subjected to a lower level of shear stress showed inhibition of MCM-induced JNK and Akt phosphorylation, NF-kappaB activation and uPA expression. The PB-MCM-induced uPA expression was suppressed by AMP-activated protein kinase (AMPK) agonist. The inhibitor or siRNA for AMPK abolished the shear-mediated inhibition of uPA expression. CONCLUSIONS: These data support the hypothesis that uPA up-regulation stimulated by macrophages may play an active role in the onset of OA and in the shear stress protection against this induction.
  Arthritis research & therapy 04/2013; 15(2):R53.
• Article: Gene-environment interaction between body mass index and transforming growth factor beta 1 (TGFbeta1) gene in knee and hip osteoarthritis.

  Stella G Muthuri, Sally Doherty, Weiya Zhang, Rose A Maciewicz, Kenneth Muir, Michael Doherty
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  ABSTRACT: INTRODUCTION: The objective was to investigate potential gene-environment interaction between body mass index (BMI) and each of eight TGFbeta1 polymorphisms in knee and hip osteoarthritis (OA). METHODS: We conducted a case-control study of Caucasian men and women aged 45-86 years from Nottingham, United Kingdom (Genetics of OA and Lifestyle [GOAL] study). Cases had clinically severe symptoms and radiographic knee or hip OA; controls had no symptoms and no radiographic knee/hip OA. We used logistic regression to investigate the association of TGFbeta1 polymorphisms and OA when stratifying by BMI. Knee and hip OA were analyzed separately with adjustment for potential confounders. Additive and multiplicative interactions were examined. RESULTS: 2048 cases (1042 knee OA, 1006 hip OA) and 967 controls were studied. For hip OA, the highest risk was in overweight (BMI[greater than or equal to]25kg/m2) individuals with the variant allele of single-nucleotide polymorphism (SNP) rs1800468 (odds ratio [OR] 2.21, 95% confidence interval [CI] 1.55-3.15). Evaluation of gene-environment interaction indicated significant synergetic interaction (relative excess risk due to interaction [RERI]=0.93, synergy index [SI]=4.33) with an attributable proportion due to interaction (AP) of 42% (AP=0.42; 95%CI 0.16-0.68). Multiplicative interaction was also significant (OR for interaction [ORINT]=2.27, p=0.015). For knee OA, the highest risk was in overweight individuals with homozygous genotype 11 of SNP rs2278422 (OR=6.95, p<0.001). In contrast, the variant allele indicated slightly lower risks (OR= 4.72, p<0.001), a significant antagonistic interaction (RERI= -2.66, SI=0.59), AP= -0.56 (95%CI -0.94- -0.17) and a significant multiplicative interaction (ORINT=0.47, p=0.013). CONCLUSION: TGFbeta1 gene polymorphisms interact with being overweight to influence the risk of large joint OA.
  Arthritis research & therapy 04/2013; 15(2):R52.
• Article: Open label study of escalating doses of oral treprostinil diethanolamine in patients with systemic sclerosis and digital ischemia: pharmacokinetics and correlation with digital perfusion.

  Ami A Shah, Elena Schiopu, Laura K Hummers, Michael Wade, Kristine Phillips, Cynthia Anderson, Robert Wise, Francesco Boin, James R Seibold, Fredrick Wigley, Kristan D Rollins
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  ABSTRACT: INTRODUCTION: Treprostinil diethanolamine is an innovative salt form of the prostacyclin analogue, treprostinil sodium, developed as an oral sustained release (SR) osmotic tablet. The availability of a formulation permitting convenient systemic delivery might have applicability to scleroderma vascular complications. We evaluated pharmacokinetics and perfusion in scleroderma patients with digital ischemia following escalating twice-daily doses of treprostinil diethanolamine SR. METHODS: In this dual-center, open-label, phase I pharmacokinetic study, scleroderma patients with digital ulcers were enrolled. Drug concentrations and perfusion, quantified by laser Doppler imaging, were measured over 12 hours at the 2mg and 4mg (or maximally tolerated) doses. Pharmacokinetic parameters were determined from individual plasma concentration versus time profiles using non-compartmental analysis methods. Digital perfusion and skin temperature were modeled as a function of log-transformed drug concentration and other covariates by performing repeated measures analyses using random effects models. RESULTS: Nineteen scleroderma patients (84% female, 53% limited scleroderma) received treprostinil diethanolamine SR with dose titration up to 4mg twice daily as tolerated. Peak concentrations (mean maximum plasma concentration [Cmax] = 1176 and 2107 pg/mL) occurred approximately 3.6 hours after dose administration, and overall exposure (under the plasma concentration-time curve from time 0 to 12 hours post dose [AUC0-12] = 7187 and 12992 hr*pg/mL) was linear between the 2mg and 4mg doses. Perfusion and digital skin temperature were positively associated with log-transformed plasma concentration at the 4mg dose (p=0.015 and p=0.013, respectively). The most frequent adverse events were similar to those seen with prostacyclin analogues. CONCLUSIONS: Oral treprostinil diethanolamine was effectively absorbed in patients with scleroderma. Drug administration was temporally associated with improved cutaneous perfusion and temperature. Treprostinil diethanolamine may provide a new therapeutic option for Raynaud's phenomenon and the peripheral vascular disease of scleroderma. Trial Registration: ClinicalTrials.gov NCT00848939.
  Arthritis research & therapy 04/2013; 15(2):R54.
• Article: Anti-inflammatory properties of a dual PPARgamma/alpha agonist muraglitazar in in vitro and in vivo models.

  Erja-Leena Paukkeri, Tiina Leppanen, Mira Lindholm, Mun Fei Yam, Mohd Zaini Asmawi, Anne Kolmonen, Paula H Aulaskari, Eeva Moilanen
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  ABSTRACT: INTRODUCTION: Peroxisome proliferator-activated receptor (PPAR) agonists are widely used drugs in the treatment of diabetes and dyslipidemia. In addition to their metabolic effects, PPAR isoforms PPARalpha and PPARgamma are also involved in the regulation of immune responses and inflammation. In the present study, we investigated the effects of a dual PPARgamma/alpha agonist muraglitazar on inflammatory gene expression in activated macrophages and on carrageenan-induced inflammation in the mouse. METHODS: J774 murine macrophages were activated by lipopolysaccharide (LPS) and treated with dual PPARgamma/alpha agonist muraglitazar, PPARgamma agonist GW1929 or PPARalpha agonist fenofibrate. The effects of PPAR agonists on cytokine production and the activation of iNOS pathway were investigated by ELISA, Griess method, western blotting and quantitative RT-PCR. Nuclear translocation, DNA-binding activity and reporter gene assays were used to assess the activity of NF-kB transcription factor. Carrageenan-induced paw oedema was used as an in vivo model of acute inflammation. RESULTS: Muraglitazar as well as PPARgamma agonist GW1929 and PPARalpha agonist fenofibrate inhibited LPS-induced iNOS expression and NO production in activated macrophages in a dose-dependent manner. Inhibition of iNOS expression by muraglitazar included both transcriptional and post-transcriptional components; the former being shared by GW1929 and later by fenofibrate. All tested PPAR agonists inhibited also IL-6 production, while TNFalpha production was reduced by muraglitazar and GW1929, but not by fenofibrate. Interestingly, the anti-inflammatory properties of muraglitazar were also translated to in vivo. This was evidenced by the finding that muraglitazar inhibited carrageenan-induced paw inflammation in a dose-dependent manner in mice as did iNOS inhibitor L-NIL and anti-inflammatory steroid dexamethasone. CONCLUSIONS: These results show that muraglitazar has anti-inflammatory properties both in vitro and in vivo and these effects reflect the agonistic action through both PPARalpha and PPARgamma.
  Arthritis research & therapy 04/2013; 15(2):R51.
• Article: Rpp25 is a major target of autoantibodies to the Th/To complex as measured by a novel chemiluminescent assay.

  Michael Mahler, Cristina Gascon, Sima Patel, Angela Ceribelli, Marvin J Fritzler, Andreas Swart, Edward Kl Chan, Minoru Satoh
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  ABSTRACT: INTRODUCTION: Autoantibodies to the Th/To antigen have been described in systemic sclerosis (SSc) and several proteins of the macromolecular Th/To complex have been reported to react with anti-Th/To antibodies. However, anti-Th/To has not been clinically utilized due to unavailability of commercial tests. The objective of the present study is to evaluate the newly developed ELISA and chemiluminescent immunoassay (CLIA) to measure autoantibodies to Rpp25 (a component of the Th/To complex) using immunoprecipitation (IP) as the reference method. METHODS: The first cohort consisted of 123 SSc patients including 7 anti-Th/To positive samples confirmed by IP. Additional anti-Th/To positive samples from non-SSc patients were also tested. For evaluation of the QUANTA Flash Rpp25 CLIA (research use only), 8 anti-Th/To IP positives, a cohort of 70 unselected SSc patients and sera from various disease controls (n=357) and random healthy individuals (n=10) were studied. RESULTS: Anti-Rpp25 antibodies determined by ELISA were found in 11/14 anti-Th/To IP positive but only in 1/156 (0.6%) negative samples resulting in a positive percent agreement of 78.6% (95% confidence interval [CI] 49.2-95.3%) and a negative percent agreement of 99.4% (95% CI 96.4-100.0%). To verify the results using a second method, 53 samples were tested by ELISA and CLIA for anti-Rpp25 reactivity and the results were highly correlated (rho=0.71, 95% CI 0.56-0.81; p<0.0001). To define the cut-off of the CLIA, anti-Th/To IP positive and negative sera were tested using the anti-Rpp25 CLIA. At the cut-off selected by receiver operating characteristic analysis 8/8 (100.0%) of the anti-Th/To positive sera but only 2/367 (0.5%) of the controls were positive for anti-Rpp25 antibodies. The positive and negative percent agreements were 100.0% (95% CI 63.1-100.0%) and 99.5% (95% CI 98.0-99.9%), respectively. In the disease cohorts 2/70 (2.9%) of the SSc patients were positive for anti-Rpp25 antibodies compared to 2/367 (0.5%) of the controls (p=0.032). Receiver operating characteristic (ROC) analysis showed discrimination between SSc patients and controls with an area under the curve (AUC) value of 0.732 (95% CI 0.655-0.809). CONCLUSION: Rpp25 is a major target of autoantibodies to the Th/To autoantigen complex. Further studies are needed to evaluate the clinical utility of the new assays.
  Arthritis research & therapy 04/2013; 15(2):R50.
• Article: microRNA-mediated regulation of innate immune response in rheumatic diseases.

  Xiaobing Luo, Koustubh Ranade, Ronel Talker, Bahija Jallal, Nan Shen, Yihong Yao
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  ABSTRACT: miRNAs have been shown to play essential regulatory roles in the innate immune system. They function at multiple levels to shape the innate immune response and maintain homeostasis by direct suppression of the expression of their target proteins, preferentially crucial signaling components and transcription factors. Studies in humans and in disease models have revealed that dysregulation of several miRNAs such as miR-146a and miR-155 in rheumatic diseases leads to aberrant production of and/or signaling by inflammatory cytokines and, thus, critically contributes to disease pathogenesis. In addition, the recent description of the role of certain extracellular miRNAs as innate immune agonist to induce inflammatory response would have direct relevance to rheumatic diseases.
  Arthritis research & therapy 04/2013; 15(2):210.
• Article: Adult and juvenile dermatomyositis: are the distinct clinical features explained by our current understanding of serological subgroups and pathogenic mechanisms?

  Sarah L Tansley, Neil J McHugh, Lucy R Wedderburn
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  ABSTRACT: Adult and juvenile dermatomyositis share the hallmark features of pathognomic skin rash and muscle inflammation, but are heterogeneous disorders with a range of additional disease features and complications. The frequency of important clinical features such as calcinosis, interstitial lung disease and malignancy varies markedly between adult and juvenile disease. These differences may reflect different disease triggers between children and adults, but whilst various viral and other environmental triggers have been implicated, results are so far conflicting. Myositis-specific autoantibodies can be detected in both adults and children with idiopathic inflammatory myopathies. They are associated with specific disease phenotypes and complications, and divide patients into clinically homogenous subgroups. Interestingly, whilst the same autoantibodies are found in both adults and children, the disease features remain different within autoantibody subgroups, particularly with regard to life-threatening disease associations, such as malignancy and rapidly progressive interstitial lung disease. Our understanding of the mechanisms that underlie these differences is limited by a lack of studies directly comparing adults and children. Dermatomyositis is an autoimmune disease, which is believed to develop as a result of an environmental trigger in a genetically predisposed individual. Age-specific host immune responses and muscle physiology may be additional complicating factors that have significant impact on disease presentation. Further study into this area may produce new insights into disease pathogenesis.
  Arthritis research & therapy 04/2013; 15(2):211.
• Article: The granulocyte colony stimulating factor pathway regulates autoantibody production in a murine induced model of systemic lupus erythematosus.

  Margareta Lantow, Ramya Sivakumar, Leilani Zeumer, Clive Wasserfall, Ying-Yi Zheng, Mark A Atkinson, Laurence Morel
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  ABSTRACT: INTRODUCTION: An NZB-derived genetic locus (Sle2c2) that suppresses autoantibody production in a mouse model of induced systemic lupus erythematosus contains a polymorphism in the gene encoding the G-CSF receptor. This study was designed to test the hypothesis that the Sle2c2 suppression is associated with an impaired G-CSF receptor function that can be overcome by exogenous G-CSF. METHODS: Leukocytes from B6.Sle2c2 and B6 congenic mice, which carry a different allele of the G-CSF receptor, were compared for their responses to G-CSF. Autoantibody production was induced with the chronic graft-versus-host-disease (cGVHD) model by adoptive transfer of B6.bm12 splenocytes. Different treatment regimens varying the amount and frequency of G-CSF (Neulasta(R)) or carrier control were tested on cGVHD outcomes. Autoantibody production, immune cell activation, and reactive oxygen species (ROS) production were compared between the two strains with the various treatments. In addition, the effect of G-CSF treatment was examined on the production autoantibodies in the B6.Sle1.Sle2.Sle3 (B6.TC) spontaneous model of lupus. RESULTS: B6.Sle2c2 and B6 leukocytes responded differently to G-CSF. G-CSF binding by B6.Sle2c2 leukocytes was reduced as compared to B6, which was associated with a reduced expansion in response to in vivo G-CSF treatment. G-CSF in vivo treatment also failed to mobilize bone-marrow B6.Sle2c2 neutrophils as it did for B6 neutrophils. In contrast, the expression of G-CSF responsive genes indicated a higher G-CSF receptor signaling in B6.Sle2c2 cells. G-CSF treatment restored the ability of B6.Sle2c2 mice to produce autoantibodies in a dose-dependent manner upon cGVHD induction, which correlated with restored CD4+ T cells activation, as well as dendritic cell and granulocyte expansion. Steady-state ROS production was higher in B6.Sle2c2 than in B6 mice. cGVHD induction resulted in a larger increase in ROS production in B6 than in B6.Sle2c2 mice, and this difference was eliminated with G-CSF treatment. Finally, a low dose G-CSF treatment accelerated the production of anti-dsDNA IgG in young B6.TC mice. CONCLUSION: The different in vivo and in vitro responses of B6.Sle2c2 leukocytes are consistent with the mutation in the G-CSFR having functional consequences. The elimination of Sle2c2 suppression of autoantibody production by exogenous G-CSF indicates that Sle2c2 corresponds to a loss of function of G-CSF receptor. This result was corroborated by the increased anti-dsDNA IgG production in G-CSF-treated B6.TC mice, which also carry the Sle2c2 locus. Overall, these results suggest that the G-CSF pathway regulates the production of autoantibodies in murine models of lupus.
  Arthritis research & therapy 04/2013; 15(2):R49.
• Article: Implications in the difference of anti-Mi-2 and -p155/140 autoantibody prevalence in two dermatomyositis cohorts from Mexico City and Guadalajara.

  Marcelo H Petri, Minoru Satoh, Beatriz T Martin-Marquez, Raul Vargas-Ramirez, Luis J Jara, Miguel A Saavedra, Claudia Cruz-Gonzalez, Lilia Andrade-Ortega, Olga L Vera-Lastra, Mario Salazar-Paramo, Rosa E Prieto-Parra, Laura Gonzalez-Lopez, Jorge I Gamez-Nava, Hermes U Ramirez-Sanchez, Jason Y F Chan, Steven J Ross, Edward K L Chan, Monica Vazquez-Del Mercado
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  ABSTRACT: INTRODUCTION: Autoantibodies and clinical manifestations in polymyositis/dermatomyositis (PM/DM) are affected by both genetic and environmental factors. High prevalence of DM and anti-Mi-2 in Central America is thought to be associated with the high UV index of the area. Prevalence of autoantibodies and clinical manifestation in PM/DM were evaluated comparing two cohorts in Mexico. METHODS: Ninety-five Mexican patients with PM/DM (66 DM, 29 PM; 67 Mexico City, 28 Guadalajara) were studied. Autoantibodies were characterized by immunoprecipitation using 35S-methionine labeled K562 cell extract. Clinical information was obtained from medical records. RESULTS: DM represented 69% of PM/DM and anti-Mi-2 was the most common autoantibody (35%), followed by anti-p155/140 (11%); however, anti-Jo-1 was only 4%. The autoantibody profile in adult-onset DM in Mexico City vs Guadalajara showed striking differences: anti-Mi-2 was 59% vs 12% (P = 0.0012) whereas anti-p155/140 was 9% vs 35% (P = 0.02). When clinical features of anti-Mi-2 (+) DM (n = 30) vs anti-Mi-2 (-) DM (n = 36) were compared, strong association of anti-Mi-2 with DM was confirmed and shawl sign (86% vs 64%, P < 0.05) was more common in anti-Mi-2 (+) group (P = 0.0001). Levels of creatine phosphokinase (CPK) were higher in anti-Mi-2 (+) but they responded well to therapy. CONCLUSIONS: Anti-Mi-2 has high prevalence in Mexican DM and is associated with shawl sign and high CPK. Prevalence of anti-Mi-2 and anti-p155/140 was significantly different in Mexico City vs Guadalajara, which have a similar UV index. This suggests roles of factors other than UV in anti-Mi-2 antibody production.
  Arthritis research & therapy 04/2013; 15(2):R48.
• Article: Why is epigenetics important in understanding the pathogenesis of inflammatory musculoskeletal diseases?

  Udo Oppermann
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  ABSTRACT: In its widest sense, the term epigenetics describes a range of mechanisms in genome function that do not solely result from the DNA sequence itself. These mechanisms comprise DNA and chromatin modifications and their associated systems, as well as the noncoding RNA machinery. The epigenetic apparatus is essential for controlling normal development and homeostasis, and also provides a means for the organism to integrate and react upon environmental cues. A multitude of functional studies as well as systematic genome-wide mapping of epigenetic marks and chromatin modifiers reveal the importance of epigenomic mechanisms in human pathologies, including inflammatory conditions and musculoskeletal disease such as rheumatoid arthritis. Collectively, these studies pave the way to identify possible novel therapeutic intervention points and to investigate the utility of drugs that interfere with epigenetic signalling not only in cancer, but possibly also in inflammatory and autoimmune diseases.
  Arthritis research & therapy 04/2013; 15(2):209.
• Article: Response to 'Ramipril attenuates lipid peroxidation and cardiac fibrosis in an experimental model of rheumatoid arthritis' - authors' reply.

  Qin Shi, Jamilah Abusarah, Ghayath Baroudi, Julio C Fernandes, Hassan Fahmi, Mohamed Benderdour
  Arthritis research & therapy 04/2013; 15(2):406.