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  1. Profiling anti-cyclic citrullinated peptide antibodies in patients with juvenile idiopathic arthritis

    PubMed Central

    2012-01-01

    Background Anti-citrullinated protein/peptide antibodies (ACPA), have high specificity for rheumatoid arthritis (RA). Some children with juvenile idiopathic arthritis (JIA), phenotypically resemble RA and test positive for rheumatoid factor (RF) a characteristic biomarker of RA. We investigated the prevalence of ACPA and its relationship to other serologic markers associated with RA in a well-characterized JIA cohort. Methods Cases were 334 children with JIA, 30 of whom had RF + polyarticular JIA. Sera from all cases and 50 healthy pediatric controls were investigated by ELISA at a single time point for anti-cyclic citrullinated peptide (anti-CCP) IgG, RF IgM, IgA and IgG, anti-RA33 IgG, and antinuclear antibodies (ANA). Comparisons between cases and controls were made using Chi-square or Fisher exact tests and T-tests. Results The prevalence of RF was 8% among controls, and 12% among cases (ns). The prevalence of ACPA was 2% in controls and 14.3% in cases (OR 8.2, p <0.01). Children who were ACPA-positive and RF-negative (n = 23) had a significantly earlier onset-age (4.6 years vs. 12.1 years, p <0.00001) and had fewer HLA-DRB1 shared epitope alleles than those positive for both RF and ACPA (n = 25). Prevalence of anti-RA33 was not different between cases and controls. Conclusions ACPAs are detectable in 14% of children with JIA. Children with positive ACPA but negative RF are frequent, and may define a distinct subset of children with JIA. ACPA testing should be included in the classification of JIA. PMID:22931121

  2. Is Anti-Cyclic Citrullinated Peptide Antibody a Good Value Biomarker for Alzheimer Disease?

    PubMed Central

    Meamar, Rokhsareh; Askari, Gholamreza; Ghasemi, Majid; Ghazvini, Mohammad Reza Aghaye; Vesal, Sahar; Sharifkhah, Mostafa; Faradonbeh, Nazanin Alaei; Dehghani, Leila

    2013-01-01

    Background: Alzheimer's disease (AD) is one of the most important neurodegenerative disorder. Anti-cyclic citrullinated peptide (anti-CCP) may all be involved in the development of vascular disease such as AD. The aim of this study is detection of seropositivity for anti-CCP antibody in AD patients. Methods: In our study, 30 patients with AD and 29 healthy controls (age and-sex matched) were recruited. Homocysteine and anti-CCP was measured by spectrophotometrically and immunoassay. Results: Mean ± SE anti-CCP was higher significantly between AD (13.6 ± 3) and healthy subjects (4.8 ± 0.2) (P = 0.006). In the patients, anti-CCP serum level was in high range (32.1%) of abnormal levels, but there was no significant difference in serum homocysteine in AD patients compared with controls. There is no correlation between anti-CCP and homocysteine levels in AD patients (P = 0.75), but between age and anti-CCP level observed a significantly correlation (P = 0.04). Conclusions: It needs more studies to clarify confirmation the role of anti-CCP antibody production in AD patients. PMID:23776724

  3. Highly sensitive immunoassay of anti-cyclic citrullinated peptide marker using surface-enhanced Raman scattering detection

    NASA Astrophysics Data System (ADS)

    Chon, H.; Lee, S.; Wang, R.; Bang, S.-Y.; Lee, H.-S.; Bae, S.-C.; Hong, S. H.; Yoon, Y. H.; Lim, D.; Choo, J.

    2015-07-01

    We report a highly sensitive anti-cyclic citrullinated peptide (anti-CCP) detection method for early diagnosis of rheumatoid arthritis (RA) using surface-enhanced Raman scattering (SERS)-based immunoassay. Herein, cyclic citrullinated peptide (CCP)-conjugated magnetic beads and anti-human IgG-conjugated hollow gold nanospheres (HGNs) were used as substrates and SERS nano-tags, respectively. First, its detection sensitivity was evaluated using anti-CCP standard solutions. Then quantitative anti-CCP levels, determined by the SERS-based assay, were compared with those obtained from three commercially available anti-CCP assay kits (Immunoscan CCPlus, ImmunnLisa™ CCP and BioPlex™ 2200) to assess its potential utility as a clinical tool. Finally, clinical samples from 20 RA patients were investigated using them. In the SERS-based assay, the anti-CCP level in human serum was successfully determined by monitoring the characteristic Raman peak intensity of SERS nano-tags. The diagnostic performance of our SERS-based immunoassay for clinical samples shows a good agreement with those measured by three commercial anti-CCP kits. In addition, our SERS-based assay results are more consistent in the low concentration range (0-25 U/mL) than those achieved by the commercial kits. Accordingly, it is estimated that the SERS-based assay is a potentially useful diagnostic tool for early diagnosis of RA.

  4. Association analysis of anti-Epstein-Barr nuclear antigen-1 antibodies, anti-cyclic citrullinated peptide antibodies, the shared epitope and smoking status in Brazilian patients with rheumatoid arthritis

    PubMed Central

    Yazbek, Michel Alexandre; de Barros-Mazon, Silvia; Rossi, Cláudio Lúcio; Londe, Ana Carolina; Costallat, Lilian Tereza Lavras; Bértolo, Manoel Barros

    2011-01-01

    INTRODUCTION: Epstein-Barr virus exposure appears to be an environmental trigger for rheumatoid arthritis that interacts with other risk factors. Relationships among anti-cyclic citrullinated peptide antibodies, the shared epitope, and smoking status have been observed in patients with rheumatoid arthritis from different populations. OBJECTIVE: To perform an association analysis of anti-Epstein-Barr nuclear antigen-1 antibodies, anti-cyclic citrullinated peptide antibodies, the shared epitope, and smoking status in Brazilian patients with rheumatoid arthritis. METHODS: In a case-control study, 140 rheumatoid arthritis patients and 143 healthy volunteers who were matched for age, sex, and ethnicity were recruited. Anti-Epstein-Barr nuclear antigen-1 antibodies and anti-cyclic citrullinated peptide antibodies were examined using an enzyme-linked immunosorbent assay, and shared epitope alleles were identified by genotyping. Smoking information was collected from all subjects. A comparative analysis of anti-Epstein-Barr nuclear antigen-1 antibodies, anti-cyclic citrullinated peptide antibodies, the shared epitope, and smoking status was performed in the patient group. Logistic regression analysis models were used to analyze the risk of rheumatoid arthritis. RESULTS: Anti-Epstein-Barr nuclear antigen-1 antibodies were not associated with anti-cyclic citrullinated peptide antibodies, shared epitope alleles, or smoking status. Anti-cyclic citrullinated peptide antibody positivity was significantly higher in smoking patients with shared epitope alleles (OR = 3.82). In a multivariate logistic regression analysis using stepwise selection, only anti-cyclic citrullinated peptide antibodies were found to be independently associated with rheumatoid arthritis (OR = 247.9). CONCLUSION: Anti-Epstein-Barr nuclear antigen-1 antibodies did not increase the risk of rheumatoid arthritis and were not associated with the rheumatoid arthritis risk factors studied. Smoking and

  5. Anti-Cyclic Citrullinated Peptide Assays Differ in Subjects at Elevated Risk for Rheumatoid Arthritis and Subjects with Established Disease

    PubMed Central

    Demoruelle, M. Kristen; Parish, Mark C.; Derber, Lezlie A.; Kolfenbach, Jason R.; Hughes-Austin, Jan M.; Weisman, Michael H.; Gilliland, William; Edison, Jess D.; Buckner, Jane H.; Mikuls, Ted R.; O’Dell, James R.; Keating, Richard M.; Gregersen, Peter K.; Norris, Jill M.; Holers, V. Michael; Deane, Kevin D.

    2013-01-01

    Objective To compare commonly-available tests for antibodies to citrullinated protein antigens (ACPAs) for diagnostic accuracy and assay agreement in established rheumatoid arthritis (RA) and subjects at elevated risk for RA. Methods ELISA testing for anti-cyclic citrullinated peptide (anti-CCP) antibodies was performed using CCP2 (Axis-Shield) and CCP3.1 (IgA/IgG INOVA) in the following subjects: 1) probands with established RA (N=340) from the Studies of the Etiology of RA (SERA), 2) first degree relatives (FDRs) without RA (family members of SERA RA probands; N=681), 3) Department of Defense Serum Repository (DoDSR) RA cases with pre-diagnosis samples (N=83; 47/83 also had post-diagnosis samples), and 4) blood-donor and DoDSR controls (N=283). Results In established RA, CCP2 was more specific (99.2% vs. 93.1%, p<0.01), but less sensitive (58.7% vs. 67.4%, p=0.01) than CCP3.1, with specificity of CCP3.1 increasing to 97.2% if levels ≥3 times the standard cut-off level were considered. In all subjects, at standard cut-off levels, CCP3.1 positivity was more prevalent. In DoDSR cases, CCP2 was more specific than CCP3.1 for a future diagnosis of RA, and higher CCP levels trended towards greater specificity for disease onset within 2 years. At standard cut-off levels, assay agreement was good in established RA (kappa=0.76), but poor in FDRs without inflammatory arthritis (kappa=0.25). Conclusion Anti-CCP assays differ to an extent that may be meaningful in diagnosing RA in patients with inflammatory arthritis, and in evaluating the natural history of RA development in subjects at-risk for future RA. Mechanisms underlying these differences in test performance need further investigation. PMID:23686569

  6. A Systematic Review of Serum Biomarkers Anti-Cyclic Citrullinated Peptide and Rheumatoid Factor as Tests for Rheumatoid Arthritis

    PubMed Central

    Taylor, Peter; Gartemann, Juliane; Hsieh, Jeanie; Creeden, James

    2011-01-01

    This systematic review assesses the current status of anti-cyclic citrullinated peptide (anti-CCP) and rheumatoid factor (RF) tests in the diagnosis and prognosis of rheumatoid arthritis (RA). We reviewed publications on tests and biomarkers for early diagnosis of RA from English-language MEDLINE-indexed journals and non-MEDLINE-indexed sources. 85 publications were identified and reviewed, including 68 studies from MEDLINE and 17 non-MEDLINE sources. Anti-CCP2 assays provide improved sensitivity over anti-CCP assays and RF, but anti-CCP2 and RF assays in combination demonstrate a positive predictive value (PPV) nearing 100%, greater than the PPV of either of the tests alone. The combination also appears to be able to distinguish between patients whose disease course is expected to be more severe and both tests are incorporated in the 2010 ACR Rheumatoid Arthritis Classification Criteria. While the clinical value of anti-CCP tests has been established, differences in cut-off values, sensitivities and specificities exist between first-, second- and third-generation tests and harmonization efforts are under way. Anti-CCP and RF are clinically valuable biomarkers for the diagnosis and prognosis of RA patients. The combination of the two biomarkers in conjunction with other clinical measures is an important tool for the diagnosis and management of RA patients. PMID:21915375

  7. Anti-cyclic citrullinated peptide (anti-CCP) and anti-mutated citrullinated vimentin (anti-MCV) relation with extra-articular manifestations in rheumatoid arthritis.

    PubMed

    Gonzalez-Lopez, Laura; Rocha-Muñoz, Alberto Daniel; Ponce-Guarneros, Manuel; Flores-Chavez, Alejandra; Salazar-Paramo, Mario; Nava, Arnulfo; Cardona-Muñoz, Ernesto German; Fajardo-Robledo, Nicte Selene; Zavaleta-Muñiz, Soraya Amali; Garcia-Cobian, Teresa; Gamez-Nava, Jorge Ivan

    2014-01-01

    We evaluated the association between anti-cyclic citrullinated peptide antibodies (anti-CCP) and anti-mutated citrullinated vimentin antibodies (anti-MCV) with the presence of extra-articular (ExRA) manifestations in 225 patients with rheumatoid arthritis (RA). Ninety-five patients had ExRA and 130 had no ExRA. There was no association of anti-CCP and anti-MCV levels with the presence of ExRA as total group (P = 0.40 and P = 0.91, resp.). Making an analysis of individual manifestations, rheumatoid nodules were associated with positivity for rheumatoid factor (RF); (P = 0.01), anti-CCP (P = 0.048), and anti-MCV (P = 0.02). Instead, RF, anti-CCP, or anti-MCV were not associated with SS, chronic anemia, or peripheral neuropathy. Levels of anti-CCP correlated with the score of the Health Assessment Questionnaire-Disability Index (HAQ-Di) (r = 0.154, P = 0.03), erythrocyte sedimentation rate (ESR); (r = 0.155, P = 0.03), and RF (P = 0.254, P < 0.001), whereas anti-MCV titres only correlated with RF (r = 0.169, P = 0.02). On adjusted analysis, ExRA was associated with longer age (P = 0.015), longer disease duration (P = 0.007), higher DAS-28 score (P = 0.002), and higher HAQ-DI score (P = 0.007), but serum levels of anti-CCP and anti-MCV were not associated. These findings show the need to strengthen the evaluation of the pathogenic mechanisms implied in each specific ExRA manifestation. PMID:24804270

  8. Impact of baseline anti-cyclic citrullinated peptide-2 antibody concentration on efficacy outcomes following treatment with subcutaneous abatacept or adalimumab: 2-year results from the AMPLE trial

    PubMed Central

    Sokolove, Jeremy; Schiff, Michael; Fleischmann, Roy; Weinblatt, Michael E; Connolly, Sean E; Johnsen, Alyssa; Zhu, Jin; Maldonado, Michael A; Patel, Salil; Robinson, William H

    2016-01-01

    Objectives To examine whether baseline anti-cyclic citrullinated peptide-2 (CCP2) antibody status and concentration correlated with clinical outcomes in patients treated with abatacept or adalimumab on background methotrexate (MTX) in the 2-year AMPLE (Abatacept versus adaliMumab comParison in bioLogic-naïvE rheumatoid arthritis subjects with background MTX) study. Methods In this exploratory analysis, anti-CCP2 antibody concentration was measured at baseline, and antibody-positive patients were divided into equal quartiles, Q1–Q4, representing increasing antibody concentrations. Clinical outcomes analysed by baseline anti-CCP2 status and quartile included change from baseline in disease activity and disability and remission rates. Results Baseline characteristics were generally comparable across quartiles and treatment groups. In both treatment groups, anti-CCP2 antibody-negative patients responded less well than antibody-positive patients. At year 2, improvements in disease activity and disability and remission rates were similar across Q1–Q3, but were numerically higher in Q4 in the abatacept group; in contrast, treatment effects were similar across all quartiles in the adalimumab group. Conclusions In AMPLE, baseline anti-CCP2 positivity was associated with a better response for abatacept and adalimumab. Patients with the highest baseline anti-CCP2 antibody concentrations had better clinical response with abatacept than patients with lower concentrations, an association that was not observed with adalimumab. Trial registration number NCT00929864. PMID:26359449

  9. Anti-Cyclic Citrullinated Peptide Antibodies and Severity of Interstitial Lung Disease in Women with Rheumatoid Arthritis

    PubMed Central

    Ponce-Guarneros, Manuel; Mejía, Mayra; Juárez-Contreras, Pablo; Corona-Sánchez, Esther Guadalupe; Rodríguez-Hernández, Tania Marlen; Salazar-Páramo, Mario; Cardona-Muñoz, Ernesto German; Celis, Alfredo; González-Lopez, Laura

    2015-01-01

    Objective. To evaluate whether serum titers of second-generation anticyclic citrullinated peptide antibodies (anti-CCP2) are associated with the severity and extent of interstitial lung disease in rheumatoid arthritis (RA-ILD). Methods. In across-sectional study, 39 RA-ILD patients confirmed by high-resolution computed tomography (HRCT) were compared with 42 RA without lung involvement (RA only). Characteristics related to RA-ILD were assessed in all of the patients and serum anti-CCP2 titers quantified. Results. Higher anti-CCP2 titers were found in RA-ILD compared with RA only (medians 77.9 versus 30.2 U/mL, P < 0.001). In the logistic regression analysis after adjustment for age, disease duration (DD), smoke exposure, disease activity, functioning, erythrocyte sedimentation rate, and methotrexate (MTX) treatment duration, the characteristics associated with RA-ILD were higher anti-CCP2 titers (P = 0.003) and + RF (P = 0.002). In multivariate linear regression, the variables associated with severity of ground-glass score were anti-CCP2 titers (P = 0.02) and with fibrosis score DD (P = 0.01), anti-CCP2 titers (P < 0.001), and MTX treatment duration (P < 0.001). Conclusions. Anti-CCP2 antibodies are markers of severity and extent of RA-ILD in HRCT. Further longitudinal studies are required to identify if higher anti-CCP2 titers are associated with worst prognosis in RA-ILD. PMID:26090479

  10. Pattern of thyroid, celiac, and anti-cyclic citrullinated peptide autoantibodies coexistence with type 1 diabetes mellitus in patients from Southwestern Saudi Arabia

    PubMed Central

    Al-Hakami, Ahmed M.

    2016-01-01

    Objectives: To investigate the seroprevalence of coexisting autoantibodies among type 1 diabetes mellitus (T1DM) patients, and to look for possible correlations with age at diagnosis, diabetes duration, and glycemic control. Methods: This is a cross-sectional study conducted at Aseer Central Hospital, Abha, Kingdom of Saudi Arabia from March 2013 to June 2014. A total of 202 T1DM patients were screened for serum anti-thyroglobulin (TG), anti-thyroid peroxidase (TPO), anti-tissue transglutaminase (aTTG), anti-endomysial (EMA), and anti-cyclic citrullinated peptide (anti-CCP) antibodies along with glycated hemoglobin, and biometric data. Results: From the 202 T1DM patients (96 males, and 106 females) (mean age: 11.3 years), 33 (16.3%) were positive for thyroid autoantibodies. Specifically, 19 (9.4%) were positive for TG and 25 (12.8%) were positive for TPO, and 11 were double positive. There were 21 (10.4%) patients that showed a double positive for both aTTG-IgA and EMA, and only one case of T1DM was positive for anti-CCP. No significant correlations were noticed between the presence of autoantibodies and the age at diagnosis, diabetes duration, body mass index, and glycemic control. Conclusion: The prevalence of thyroid and celiac disease autoantibodies is high among T1DM patients, while anti-CCP remains low and might be weakly associated with T1DM in the southwestern region of Saudi Arabia. No significant correlation between the age at T1DM diagnosis, duration, and glycemic control, and the presence of autoantibodies was found. PMID:27052281

  11. Low-field magnetic resonance imaging or combined ultrasonography and anti-cyclic citrullinated peptide antibody improve correct classification of individuals as established rheumatoid arthritis: results of a population-based, cross-sectional study

    PubMed Central

    2014-01-01

    Background The aim of the present study was to evaluate the accuracy of two approaches using magnetic resonance imaging (MRI) or combined ultrasonography (US) and anti-cyclic citrullinated peptide antibody (ACPA) for diagnosis and classification of individuals with established rheumatoid arthritis (RA). Methods In 53 individuals from a population-based, cross-sectional study, historic fulfilment of the American College of Rheumatology (ACR) 1987 criteria (“classification”) or RA diagnosed by a rheumatologist (“diagnosis”) were used as standard references. The sensitivity, specificity and Area under Curve for Receiver Operating Characteristics curves (ROC-area: (sensitivity + specificity)/2) were calculated for “current fulfilment of the ACR 1987 criteria” (list format), “adapted ACR 1987 criteria” (list format, substituting IgM rheumatoid factor with ACPA and clinical joint swelling and erosions on radiography with synovitis and erosions detected by US on a semi-quantitative scale), and RA MRI scoring System (RAMRIS) scores on low-field MRI in the unilateral hand. Results For the ACR 1987 criteria the ROC-area was 75% (sensitivity/specificity = 50%/100%) (with “classification” as standard reference) and 69% (44%/94%) (with “diagnosis” as standard reference), while for the adapted ACR 1987 criteria it was 86% (75%/97%) (classification) and 82% (72%/91%) (diagnosis). For RAMRIS synovitis score in metacarpophalangeal (MCP) joints only (cut-off ≥5), the ROC-area (sensitivity/specificity) was 78% (62%/94%) (classification) and 85% (69%/100%) (diagnosis), while for the total synovitis score of MCP joints plus wrist (cut-off ≥10) it was 78% (62%/94%) (both classification and diagnosis). Conclusions Compared with the ACR 1987 criteria, low-field MRI alone or adapted criteria incorporating US and ACPA increased the correct classification and diagnosis of RA. PMID:25103610

  12. Evaluation of anti-citrullinated type II collagen and anti-citrullinated vimentin antibodies in patients with juvenile idiopathic arthritis

    PubMed Central

    2013-01-01

    Background To determine the prevalence and significance of anti-citrullinated vimentin and anti-citrullinated type II collagen antibodies and elucidate their role in the disease process of juvenile idiopathic arthritis (JIA). Methods Sera were obtained from 95 patients with various subtypes of JIA, 19 systemic lupus erythematosus (SLE) patients, and 10 healthy children. Antibodies were measured in the sera against citrullinated and native type II collagen and vimentin (vim1-16 and vim 59-74) by enzyme-linked immunosorbent assay. Samples were compared to anti-cyclic citrullinated peptide (anti-CCP) antibody and rheumatoid factor (RF) isotypes, and our previously measured anti-citrullinated fibrinogen and α-enolase antibodies on the same patient population, in addition to erythrocyte sedimentation rate and C-reactive protein. The relationship between the anti-citrullinated antibody profile and disease activity and joint damage were also investigated. Results Twenty-three JIA patients (24%) demonstrated reactivity to anti-citrullinated type II collagen. Ten JIA patients (10.5%) demonstrated reactivity to anti-citrullinated vimentin 1–16 antibodies and 7 (7.4%) to anti-citrullinated vimentin 59–74 antibodies. One IgM RF-positive polyarticular patient was positive for all 5 of the citrullinated autoantibodies tested. Thirty-seven different subsets of patients were identified based on their anti-citrullinated autoantibody and RF isotype profile. No significant associations were noted with anti-citrullinated type II collagen and anti-citrullinated vimentin antibodies with joint damage or disease activity. Anti-citrullinated vimentin 59–74 antibodies demonstrated the highest overall specificity at 89.7%, with anti-citrullinated vimentin 1–16 and anti-citrullinated type II collagen antibodies at 86.2%. Conclusion This study demonstrates that antibodies to multiple citrullinated epitopes are present in the sera of patients with various subtypes of JIA. It also

  13. Autoimmunity: lungs and citrullination.

    PubMed

    Klareskog, Lars; Catrina, Anca I

    2015-05-01

    Anti-citrullinated protein antibodies are a distinctive feature of a subset of patients with rheumatoid arthritis (RA). A new report investigates how lung inflammation in patients with chronic obstructive pulmonary disease affects protein citrullination, providing an additional piece of information on the potential link between airway inflammation and RA. PMID:25776950

  14. Immune recognition of citrullinated epitopes.

    PubMed

    Nguyen, Hai; James, Eddie A

    2016-10-01

    Conversion of arginine into citrulline is a post-translational modification that is observed in normal physiological processes. However, abnormal citrullination can provoke autoimmunity by generating altered self-epitopes that are specifically targeted by autoantibodies and T cells. In this review we discuss the recognition of citrullinated antigens in human autoimmune diseases and the role that this modification plays in increasing antigenic diversity and circumventing tolerance mechanisms. Early published work demonstrated that citrullinated proteins are specifically targeted by autoantibodies in rheumatoid arthritis and that citrullinated peptides are more readily presented to T cells by arthritis-susceptible HLA class II 'shared epitope' proteins. Emerging data support the relevance of citrullinated epitopes in other autoimmune diseases, including type 1 diabetes and multiple sclerosis, whose susceptible HLA haplotypes also preferentially present citrullinated peptides. In these settings, autoimmune patients have been shown to have elevated responses to citrullinated epitopes derived from tissue-specific antigens. Contrasting evidence implicates autophagy or perforin and complement-mediated membrane attack as inducers of ectopic citrullination. In either case, the peptidyl deiminases responsible for citrullination are activated in response to inflammation or insult, providing a mechanistic link between this post-translational modification and interactions with the environment and infection. As such, it is likely that immune recognition of citrullinated epitopes also plays a role in pathogen clearance. Indeed, our recent data suggest that responses to citrullinated peptides facilitate recognition of novel influenza strains. Therefore, increased understanding of responses to citrullinated epitopes may provide important insights about the initiation of autoimmunity and recognition of heterologous viruses. PMID:27531825

  15. Additional diagnostic and clinical value of anti-cyclic citrullinated peptide antibodies compared with rheumatoid factor isotypes in rheumatoid arthritis.

    PubMed

    Vallbracht, Inka; Helmke, Klaus

    2005-07-01

    In the past decade significant advantages have been made in the treatment of rheumatoid arthritis (RA) and therapeutic strategies have changed a lot. These days, highly effective disease modifying anti-rheumatic drugs enable intervention early in the disease process, in order to prevent major joint damage. For years, serological support in the diagnosis of RA has been limited to the presence of rheumatoid factors, although not very specific for RA. During the last years a variety of circulating non-RF antibodies have been discovered and reported to be of potential diagnostic value. CCP2 proved to be a very disease-specific and even sensitive marker for RA. In addition to the diagnostic properties, CCP showed to be a good prognostic marker, CCP helps to predict the erosive or nonerosive progression of the disease, and CCP is already present early in the disease. This diagnostic tool enables the clinician to choose the optimal therapeutic management for each single RA patient. PMID:16081030

  16. Interrelationships between glutamine and citrulline metabolism

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article analyzes the contribution of glutamine to the synthesis of citrulline and reviews the evidence that glutamine supplementation increases citrulline production. Glutamine supplementation has been proposed in the treatment of critically ill patients; however, a recent large multicenter ran...

  17. Detection and Quantification of Citrullinated Chemokines

    PubMed Central

    Moelants, Eva A. V.; Van Damme, Jo; Proost, Paul

    2011-01-01

    Background Posttranslational deimination or citrullination by peptidylarginine deiminases (PAD) regulates the biological function of proteins and may be involved in the development of autoimmune diseases such as rheumatoid arthritis and multiple sclerosis. This posttranslational modification of arginine was recently discovered on inflammatory chemokines including CXCL8 and CXCL10, and significantly reduced their biological activity. To evaluate the importance of these modified chemokines in patients, methods for the detection and quantification of citrullinated chemokines are needed. Since citrullination only results in an increase of the protein mass with one mass unit and the loss of one positive charge, selective biochemical detection is difficult. Therefore, we developed an antibody-based method to specifically detect and quantify citrullination on a protein of interest. Methodology/Principal Findings First, the citrullinated proteins were chemically modified with antipyrine and 2,3-butanedione at low pH. Such selectively modified citrullines were subsequently detected and quantified by specific antibodies raised against a modified citrulline-containing peptide. The specificity of this two-step procedure was validated for citrullinated CXCL8 ([Cit5]CXCL8). Specific detection of [Cit5]CXCL8 concentrations between 1 and 50 ng/ml was possible, also in complex samples containing an excess of contaminating proteins. This novel detection method was used to evaluate the effect of lipopolysaccharide (LPS) on the citrullination of inflammatory chemokines induced in peripheral blood mononuclear cells (PBMCs) and granulocytes. LPS had no significant effect on the induction of CXCL8 citrullination in human PBMCs and granulocytes. However, granulocytes, known to contain PAD, were essential for the production of significant amounts of [Cit5]CXCL8. Conclusion/Significance The newly developed antibody-based method to specifically detect and quantify chemically modified

  18. Determination of citrulline in watermelon rind.

    PubMed

    Rimando, Agnes M; Perkins-Veazie, Penelope M

    2005-06-17

    Watermelon (Citrullus vulgaris Schrad.) is a natural and rich source of the non-essential amino acid citrulline. Citrulline is used in the nitric oxide system in humans and has potential antioxidant and vasodilatation roles. A method using gas chromatography-mass spectrometry (GC-MS) was developed to separate citrulline from glutamic acid, which co-elute when analyzed by high performance liquid chromatography. Watermelons were analyzed by GC-MS to determine the citrulline content among varieties, types, flesh colors, and tissues. Citrulline content ranged from 3.9 to 28.5 mg/g dry weight (dwt) and was similar between seeded and seedless types (16.6 and 20.3 mg/g dwt, respectively). Red flesh watermelons had slightly less citrulline than the yellow or orange flesh watermelons (7.4, 28.5 and 14.2 mg/g dwt, respectively). Rind contained more citrulline than flesh on a dry weight basis (24.7 and 16.7 mg/g dwt, respectively) but a little less on a fresh weight (fwt) basis (1.3 and 1.9 mg/g fwt, respectively). These results indicate that watermelon rind, an underutilized agricultural waste, offers a source of natural citrulline. PMID:16007998

  19. Diagnostic value of antibodies against a modified citrullinated vimentin in rheumatoid arthritis

    PubMed Central

    Dejaco, Christian; Klotz, Werner; Larcher, Heike; Duftner, Christina; Schirmer, Michael; Herold, Manfred

    2006-01-01

    Antibodies directed against citrullinated vimentin are members of the family of autoantibodies reactive with citrullinated proteins and are among the most specific serological markers for the diagnosis of rheumatoid arthritis (RA). This study was performed to test the diagnostic value of a newly developed enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies against a genetically modified citrullinated vimentin (anti-MCV) in comparison with a second-generation anti-cyclic citrullinated peptides (anti-CCP2) ELISA test system. Blinded sera from 631 patients (409 consecutive out-patients and 222 randomly selected stored sera) with RA (n = 164) and non-RA (osteoarthritis [n = 120], polymyalgia rheumatica/giant cell arteritis [n = 80], spondyloarthritis [n = 36], and other inflammatory rheumatic or non-inflammatory disease [n = 67]) were tested for the presence of anti-MCV and anti-CCP2 antibodies according to the manufacturers' instructions. The diagnostic performance of the anti-MCV was comparable with the anti-CCP2 assay for the diagnosis of RA according to the calculated area under the curve (0.824; 95% confidence interval (CI) 0.778–0.870 versus 0.818; 95% CI 0.767–0.869) as analysed by receiving operating characteristic curve. When categorised with a cutoff value of 20.0 U/ml (as recommended by the manufacturer), sensitivity and specificity of the anti-MCV ELISA were 69.5% (95% CI 61.9%–76.5%) and 90.8% (86.9%–93.8%), respectively, compared with 70.1% (62.5%–77.0%) and 98.7% (96.7%–99.6%) of the anti-CCP2 assay. Using the cutoff values of 19.0 U/ml and 81.5 U/ml for the anti-MCV test to obtain a sensitivity and specificity identical to the anti-CCP2 assay, showed a reduced specificity (89.8%; 85.8%–92.9%) and sensitivity (53.7%; 45.7%–61.5%), respectively, of the anti-MCV ELISA compared with the anti-CCP2 test. In conclusion, the serum ELISA testing for anti-MCV antibodies as well as the anti-CCP-2 assay perform comparably well

  20. Detection and identification of protein citrullination in complex biological systems.

    PubMed

    Clancy, Kathleen W; Weerapana, Eranthie; Thompson, Paul R

    2016-02-01

    Protein citrullination is a post-translational modification of arginine that is catalyzed by the Protein Arginine Deiminase (PAD) family of enzymes. Aberrantly increased citrullination is associated with a host of inflammatory diseases and cancer and PAD inhibitors have shown remarkable efficacy in a range of diseases including rheumatoid arthritis, lupus, atherosclerosis, and ulcerative colitis. In rheumatoid arthritis, citrullinated proteins serve as key antigens for rheumatoid arthritis-associated autoantibodies. These data suggest that citrullinated proteins may serve more generally as biomarkers of specific disease states, however, the identification of citrullinated residues remains challenging due to the small 1Da mass change that occurs upon citrullination. Herein, we highlight the available techniques to identify citrullinated proteins/residues focusing on advanced MS techniques as well as chemical derivatization strategies that are currently being employed to identify citrullinated proteins as well as the specific residues modified within those proteins. PMID:26517730

  1. Hearing impairment in patients with rheumatoid arthritis: association with anti-citrullinated protein antibodies.

    PubMed

    Lobo, Fabrício Silva; Dossi, Mario Orlando; Batista, Lígia; Shinzato, Márcia Midori

    2016-09-01

    It has been suggested that hearing impairment (HI) is one of the extra-articular features of rheumatoid arthritis (RA). Nevertheless, the prevalence and nature of HI in RA is still uncertain. The objectives were to study hearing function in patients with RA using audiometric tests and to examine whether HI correlates with autoantibodies. Hearing functions were investigated in 43 consecutive RA patients and 23 control subjects (less than 60 years old). Their sera were evaluated for the presence of rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP), and anti-mutated citrullinated vimentin (anti-MCV) antibodies. HI was observed in 46.5 % of RA patients and in 30.4 % of control subjects, p = 0.32. HI was characterized as sensorineural in 80 and 85.7 % of RA patients and control subjects with HI, respectively, p = 1.00. RA patients had a worse hearing threshold for air conduction at 6 kHz in the right ear (p = 0.019) and had a decreased amplitude of otoacoustic emissions (OAEs) at 2 kHz bilaterally (p = 0.04) compared with control subjects. In the RA group, patients with and without HI were 80 and 34.78 % anti-CCP positive, respectively, p = 0.008. RA patients with and without HI were 85 and 43.48 % anti-MCV positive, respectively, p = 0.013. HI in RA patients was mainly sensorineural and was associated with anti-CCP and anti-MCV antibodies. PMID:27112144

  2. Effect of tobacco smoking on tissue protein citrullination and disease progression in patients with rheumatoid arthritis

    PubMed Central

    Alsalahy, Mahmoud M.; Nasser, Hamdy S.; Hashem, Manal M.; Elsayed, Sahar M.

    2010-01-01

    The aim of the present work was to study the effect of tobacco smoking on disease progression in rheumatoid arthritis patients and its relation to anti-cyclical citrullinated peptide (anti-CCP) antibodies. The study included 54 patients; 20 non-smokers, 9 ex-smokers, 14 mild to moderate smokers and 11 heavy smokers. Fifteen normal volunteers were also studied as controls. Disease stage was clinically and radiologically determined, rheumatoid factor (RF) and anti-CCP antibodies were measured in serum. Higher percentage of severe disease (stage III) was seen in heavy smoker patients than mild to moderate smokers (54.6% versus 35.7%) and in moderate smokers than ex-smokers (35.7% versus 33.6%). Lowest percentage of severe disease was seen in non-smokers (15%). RF and anti-CCP were significantly higher in smoker than non-smoker and in heavy than mild to moderate smoker patients (p < 0.01, p < 0.05 and p < 0.01, p < 0.001, respectively). In smoker patients, both RF and anti-CCP antibodies correlated significantly and positively with smoking index (r = 0.581, p < 0.001; r = 0.661, p < 0.001). Also, smoking index and anti-CCP correlated significantly and positively with disease stage (r = 0.424, p < 0.05; r = 0.523, p < 0.01). It appears from our results that, tobacco smoking mostly play a role in progression of rheumatoid arthritis through tissue protein citrullination. So all rheumatoid arthritis patients must quit completely to achieve a good control. PMID:23960723

  3. Effect of tobacco smoking on tissue protein citrullination and disease progression in patients with rheumatoid arthritis.

    PubMed

    Alsalahy, Mahmoud M; Nasser, Hamdy S; Hashem, Manal M; Elsayed, Sahar M

    2010-04-01

    The aim of the present work was to study the effect of tobacco smoking on disease progression in rheumatoid arthritis patients and its relation to anti-cyclical citrullinated peptide (anti-CCP) antibodies. The study included 54 patients; 20 non-smokers, 9 ex-smokers, 14 mild to moderate smokers and 11 heavy smokers. Fifteen normal volunteers were also studied as controls. Disease stage was clinically and radiologically determined, rheumatoid factor (RF) and anti-CCP antibodies were measured in serum. Higher percentage of severe disease (stage III) was seen in heavy smoker patients than mild to moderate smokers (54.6% versus 35.7%) and in moderate smokers than ex-smokers (35.7% versus 33.6%). Lowest percentage of severe disease was seen in non-smokers (15%). RF and anti-CCP were significantly higher in smoker than non-smoker and in heavy than mild to moderate smoker patients (p < 0.01, p < 0.05 and p < 0.01, p < 0.001, respectively). In smoker patients, both RF and anti-CCP antibodies correlated significantly and positively with smoking index (r = 0.581, p < 0.001; r = 0.661, p < 0.001). Also, smoking index and anti-CCP correlated significantly and positively with disease stage (r = 0.424, p < 0.05; r = 0.523, p < 0.01). It appears from our results that, tobacco smoking mostly play a role in progression of rheumatoid arthritis through tissue protein citrullination. So all rheumatoid arthritis patients must quit completely to achieve a good control. PMID:23960723

  4. Mutated citrullinated vimentin antibodies in rheumatoid arthritis.

    PubMed

    Kuna, Andrea Tesija

    2012-01-18

    Rheumatoid arthritis (RA) is the most common inflammatory systemic autoimmune disease, primarily affecting the peripheral joints. The past decade has been marked with revolutionary changes both in the therapeutic and diagnostic perspectives of RA. The discovery of an RA-specific citrullination-driven immune reaction gave a substantial contribution in the diagnostic approach to RA. Efforts directed towards the identification of the antigenic target specifically recognized by these autoantibodies resulted in the identification of vimentin in citrullinated form as the potential native antigen, among other proteins. Furthermore, it was found that the mutation of vimentin represents an independent trigger of antigenic properties, in addition to citrullination. As a result of this discovery, a commercial ELISA using mutated citrullinated vimentin (MCV) was developed. Increasingly, data now support the use of anti-MCV in RA diagnosis and prognosis for errosion. This review summarizes the research to date on the use of anti-MCV in RA diagnosis and prognosis and its potential use as a therapeutic marker. The pathologic role of these antibodies in RA disease is also discussed. PMID:22037509

  5. Extrarenal citrulline disposal in mice with impaired renal function

    PubMed Central

    Didelija, Inka C.; Fiorotto, Marta L.

    2014-01-01

    The endogenous synthesis of arginine, a semiessential amino acid, relies on the production of citrulline by the gut and its conversion into arginine by the kidney in what has been called the “intestinal-renal axis” for arginine synthesis. Although the kidney is the main site for citrulline disposal, it only accounts for ∼60–70% of the citrulline produced. Because the only known fate for citrulline is arginine synthesis and the enzymes that catalyze this reaction are widespread among body tissues, we hypothesized that citrulline can be utilized directly by tissues to meet, at least partially, their arginine needs. To test this hypothesis, we used stable and radioactive tracers in conscious, partially nephrectomized (½ and ⅚) and anesthetized acutely kidney-ligated mouse models. Nephrectomy increased plasma citrulline concentration but did not affect citrulline synthesis rates, thus reducing its clearance. Nephrectomy (⅚) reduced the amount of citrulline accounted for as plasma arginine from 88 to 42%. Acute kidney ligation increased the half-life and mean retention time of citrulline. Whereas the rate of citrulline conversion into plasma arginine was reduced, it was not eliminated. In addition, we observed direct utilization of citrulline for arginine synthesis and further incorporation into tissue protein in kidney-ligated mice. These observations indicate that a fraction of the citrulline produced is utilized directly by multiple tissues to meet their arginine needs and that extrarenal sites contribute to plasma arginine. Furthermore, when the interorgan synthesis of arginine is impaired, these extrarenal sites are able to increase their rate of citrulline utilization. PMID:25056350

  6. Extrarenal citrulline disposal in mice with impaired renal function

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The endogenous synthesis of arginine, a semiessential amino acid, relies on the production of citrulline by the gut and its conversion into arginine by the kidney in what has been called the "intestinal-renal axis" for arginine synthesis. Although the kidney is the main site for citrulline disposal,...

  7. Enteral arginase II provides ornithine for citrulline synthesis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The synthesis of citrulline from arginine in the small intestine depends on the provision of ornithine. To test the hypothesis that arginase II plays a central role in the supply of ornithine for citrulline synthesis, the contribution of dietary arginine, glutamine, and proline was determined by uti...

  8. Antibodies to Citrullinated Protein Antigens (ACPAs): Clinical and Pathophysiologic Significance

    PubMed Central

    Demoruelle, M. Kristen; Deane, Kevin

    2014-01-01

    Antibodies to citrullinated protein antigens (ACPAs) are highly specific for rheumatoid arthritis (RA) and are useful in the diagnosis of RA as well as the prediction of the course and outcomes of disease. Multiple methodologies exist for measuring ACPAs, including the widely available tests for anticyclic citrullinated peptide antibodies and for antibodies to mutated/modified citrullinated vimentin. These methodologies overall have similar diagnostic accuracies for RA, although there is some variability. The discovery of ACPAs and the biology of citrullination have also led to important advances in the understanding of the pathophysiology and development of RA, especially regarding the relationship between potential genetic and environmental risk factors for RA. Going forward, research into autoimmunity to citrullinated proteins may help identify the specific etiology of RA and provide approaches for the prediction of future risk of disease, and ultimately prevention of RA. PMID:21713412

  9. Citrullination and Carbamylation in the Pathophysiology of Rheumatoid Arthritis

    PubMed Central

    Pruijn, Ger J. M.

    2015-01-01

    The discovery that citrullination was crucial for the recognition of antigens by the most disease-specific class of autoantibodies in rheumatoid arthritis (RA) had a huge impact on studies aimed at understanding autoimmunity in this disease. In addition to the detailed characterization of anti-citrullinated protein antibodies, various studies have addressed the identity of citrullinated antigens. These investigations were facilitated by new methods to characterize these proteins, the analysis of protein citrullination by peptidylarginine deiminases, the generation of a catalog of citrullinated proteins present in the inflamed joints of patients and the finding that the formation of extracellular traps is dependent on the activity of peptidylarginine deiminase activity. Recently, it was found that in addition to citrullination also carbamylation, which results in chemically highly related modified proteins, yields antigens that are targeted by rheumatoid arthritis patient sera. Here, all of these aspects will be discussed, culminating in current ideas about the involvement of citrullination and carbamylation in pathophysiological processes in autoimmunity, especially RA. PMID:25964785

  10. Citrullinated Autoantigens: From Diagnostic Markers to Pathogenetic Mechanisms.

    PubMed

    Muller, Sylviane; Radic, Marko

    2015-10-01

    The conversion of an arginine residue in a protein to a citrulline residue, a reaction carried out by enzymes called peptidylarginine deiminases (PADs), is rather subtle. One of the terminal imide groups in arginine is replaced by oxygen in citrulline, thus resulting in the loss of positive charge and the gain of 1 dalton. This post-translational modification by PAD enzymes is conserved in vertebrates and affects specific substrates during development and in various mature cell lineages. Citrullination offers a unique perspective on autoimmunity because PAD activity is stringently regulated, yet autoantibodies to citrullinated proteins predictably arise. Autoantigens recognized by anti-citrullinated protein antibodies (ACPA) include extracellular proteins such as filaggrin, collagen II, fibrinogen, and calreticulin; membrane-associated proteins such as myelin basic protein; cytoplasmic proteins such as vimentin and enolase; and even nuclear proteins such as histones. Some ACPA are remarkably effective as diagnostics in autoimmune disorders, most notably rheumatoid arthritis (RA). Several ACPA can be observed before other clinical RA manifestations are apparent. In patients with RA, ACPA may attain a sensitivity that exceeds 70 % and specificity that approaches 96-98 %. The biological context that may account for the induction of ACPA emerges from studies of the cellular response of the innate immune system to acute or chronic stimuli. In response to infections or inflammation, neutrophil granulocytes activate PAD, citrullinate multiple autoantigens, and expel chromatin from the cell. The externalized chromatin is called a neutrophil extracellular "trap" (NET). Citrullination of core and linker histones occurs prior to the release of chromatin from neutrophils, thus implicating the regulation of citrullinated chromatin release in the development of autoreactivity. The citrullination of extracellular autoantigens likely follows the release of NETs and associated PADs

  11. Identification and Characterization of Citrulline-modified Brain Proteins by Combining HCD and CID Fragmentation

    PubMed Central

    Jin, Zhicheng; Fu, Zongming; Yang, Jun; Troncosco, Juan; Everett, Allen D.; Van Eyk, Jennifer E.

    2016-01-01

    Citrullination is a protein post-translational modification of arginine residues catalyzed by peptidylarginine deiminase. Protein citrullination has been detected in the central nervous system and associated with a number of neurological diseases. However, identifying citrullinated proteins from complex mixtures and pinpointing citrullinated residues has been limited. Using reversed-phase liquid chromatography and high resolution mass spectrometry, this study determined in vitro citrullination sites of glial fibrillary acid protein (GFAP) and myelin basic protein (MBP) and in vivo sites in brain protein extract. Human GFAP has five endogenous citrullination sites, R30, R36, R270, R406, and R416, and MBP has fourteen in vivo citrullination sites. Human neurogranin (NRGN/RC3) was found citrullinated at residue R68. The sequence of citrullinated peptides and citrullination sites were confirmed from peptides identified in trypsin, Lys-C, and Glu-C digests. The relative ratio of citrullination was estimated by simultaneous identification of citrullinated and unmodified peptides from Alzheimer’s and control samples. The site occupancy of citrullination at the residue R68 of NRGN ranged from 1.6% to 9.5%. Compared to collision-induced dissociation (CID), higher-energy collisional dissociation (HCD) mainly produced protein backbone fragmentation for citrullinated peptides. CID triggered HCD fragmentation is an optimal approach for the identification of citrullinated peptides in complex protein digests. PMID:23828821

  12. CCP

    MedlinePlus

    ... Home Visit Global Sites Search Help? Cyclic Citrullinated Peptide Antibody Share this page: Was this page helpful? ... Citrulline Antibody; Anti-citrulline Antibody; Anti-cyclic Citrullinated Peptide; Anti-CCP; ACPA Formal name: Cyclic Citrullinated Peptide ...

  13. Citrullinated vimentin as an important antigen in immune complexes from synovial fluid of rheumatoid arthritis patients with antibodies against citrullinated proteins

    PubMed Central

    2010-01-01

    Introduction Rheumatoid arthritis (RA) is an inflammatory disease, which results in destruction of the joint. The presence of immune complexes (IC) in serum and synovial fluid of RA patients might contribute to this articular damage through different mechanisms, such as complement activation. Therefore, identification of the antigens from these IC is important to gain more insight into the pathogenesis of RA. Since RA patients have antibodies against citrullinated proteins (ACPA) in their serum and synovial fluid (SF) and since elevated levels of citrullinated proteins are detected in the joints of RA patients, citrullinated antigens are possibly present in IC from RA patients. Methods IC from serum of healthy persons, serum of RA patients and IC from synovial fluid of RA patients and Spondyloarthropathy (SpA) patients were isolated by immunoprecipitation. Identification of the antigens was performed by SDS-PAGE, mass spectrometry and immunodetection. The presence of citrullinated proteins was evaluated by anti-modified citrulline (AMC) staining. Results Circulating IC in the serum of RA patients and healthy controls contain fibrinogenβ and fibronectin, both in a non-citrullinated form. Additionally, in IC isolated from RA SF, fibrinogenγ and vimentin were identified as well. More importantly, vimentin and a minor portion of fibrinogenβ were found to be citrullinated in the isolated complexes. Moreover these citrullinated antigens were only found in ACPA+ patients. No citrullinated antigens were found in IC from SF of SpA patients. Conclusions Citrullinated fibrinogenβ and citrullinated vimentin were found in IC from SF of ACPA+ RA patients, while no citrullinated antigens were found in IC from SF of ACPA- RA patients or SpA patients or in IC from serum of RA patients or healthy volunteers. The identification of citrullinated vimentin as a prominent citrullinated antigen in IC from SF of ACPA+ RA patients strengthens the hypothesis that citrullinated vimentin

  14. Citrullination regulates pluripotency and histone H1 binding to chromatin

    NASA Astrophysics Data System (ADS)

    Christophorou, Maria A.; Castelo-Branco, Gonçalo; Halley-Stott, Richard P.; Oliveira, Clara Slade; Loos, Remco; Radzisheuskaya, Aliaksandra; Mowen, Kerri A.; Bertone, Paul; Silva, José C. R.; Zernicka-Goetz, Magdalena; Nielsen, Michael L.; Gurdon, John B.; Kouzarides, Tony

    2014-03-01

    Citrullination is the post-translational conversion of an arginine residue within a protein to the non-coded amino acid citrulline. This modification leads to the loss of a positive charge and reduction in hydrogen-bonding ability. It is carried out by a small family of tissue-specific vertebrate enzymes called peptidylarginine deiminases (PADIs) and is associated with the development of diverse pathological states such as autoimmunity, cancer, neurodegenerative disorders, prion diseases and thrombosis. Nevertheless, the physiological functions of citrullination remain ill-defined, although citrullination of core histones has been linked to transcriptional regulation and the DNA damage response. PADI4 (also called PAD4 or PADV), the only PADI with a nuclear localization signal, was previously shown to act in myeloid cells where it mediates profound chromatin decondensation during the innate immune response to infection. Here we show that the expression and enzymatic activity of Padi4 are also induced under conditions of ground-state pluripotency and during reprogramming in mouse. Padi4 is part of the pluripotency transcriptional network, binding to regulatory elements of key stem-cell genes and activating their expression. Its inhibition lowers the percentage of pluripotent cells in the early mouse embryo and significantly reduces reprogramming efficiency. Using an unbiased proteomic approach we identify linker histone H1 variants, which are involved in the generation of compact chromatin, as novel PADI4 substrates. Citrullination of a single arginine residue within the DNA-binding site of H1 results in its displacement from chromatin and global chromatin decondensation. Together, these results uncover a role for citrullination in the regulation of pluripotency and provide new mechanistic insights into how citrullination regulates chromatin compaction.

  15. Elevated plasma citrulline: look for dihydrolipoamide dehydrogenase deficiency.

    PubMed

    Haviv, Ruby; Zeharia, Avraham; Belaiche, Corinne; Haimi Cohen, Yishai; Saada, Ann

    2014-02-01

    The E3 subunit of the pyruvate dehydrogenase complex (dihydrolipoamide dehydrogenase/dihydrolipoyl dehydrogenase/DLD/lipoamide dehydrogenase/LAD), is a mitochondrial matrix enzyme and also a part of the branched-chain ketoacid dehydrogenase and alpha-ketoglutarate dehydrogenase complexes. DLD deficiency (MIM #246900), is relatively frequent in the Ashkenazi Jewish population but occurs in other populations as well. Early diagnosis is important to prevent episodes of metabolic decompensation, liver failure, and encephalopathy. The clinical presentations are varied and may include Reye-like syndrome, hepatic failure, myopathy, and myoglobinuria. Laboratory markers, such as elevated urinary alpha-ketoglutarate, blood pyruvate, lactate, and ammonia, are mostly nonspecific and not always present, making the diagnosis difficult. Since we observed elevated plasma citrulline levels in a number of confirmed cases, we retrospectively examined the value of citrulline as a biochemical marker for DLD deficiency. Data was gathered from the files of 17 pediatric patients with DLD deficiency, confirmed by enzymatic and genetic analysis. The control group included 19 patients in whom urea cycle defects were ruled out but DLD deficiency was suspected. Seven of the DLD-deficient patients presented with elevated plasma citrulline levels (median value 205 μM, range 59-282 μM) (normal range 1-45 μM) while none in the control patient group. In five patients, elevated citrulline was associated with elevated plasma glutamine and metabolic acidosis. Interestingly, elevated plasma citrulline was associated with the common G229C mutation. In conclusion, we suggest that elevated plasma citrulline in the absence of urea cycle defects warrants an investigation for DLD deficiency. PMID:23995961

  16. Glutamine: Precursor or nitrogen donor for citrulline synthesis?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although glutamine is considered the main precursor for citrulline synthesis, the current literature does not differentiate between the contribution of glutamine carbon skeleton, versus nonspecific nitrogen (i.e., ammonia) and carbon derived from glutamine oxidation. To elucidate the role of glutami...

  17. Arginine utilization of citrulline synthesis in arginase II knockout mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The synthesis of citrulline (Cit) from arginine (Arg) in the small intestine depends on the activity of arginase II (ARG2). To test the hypothesis that Arg is the main dietary precursor for Cit synthesis, despite the lack of ARG2, tracer studies were conducted in WT and ARG2 ko conscious mice. WT mi...

  18. Glutamine: precursor or nitrogen donor for citrulline synthesis?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glutamine (Gln) is considered the main precursor for citrulline (Cit) synthesis, but no attempts have been made to differentiate the contribution of Gln carbon (Gln-C) skeleton vs. the nonspecific contribution through NH3 and CO2. To study the contribution of dietary Gln-N to the synthesis of Cit, t...

  19. Precursors for ornithine and citrulline synthesis in neonatal pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrulline (CIT) is an amino acid synthesized by gut and utilized for the synthesis of the conditionally essential amino acid arginine (ARG). In turn, the immediate precursor for CIT synthesis, ornithine (ORN), can originate from proline (PRO) and glutamine (GLN) via ornithine aminotransferase (OAT,...

  20. Citrulline immunohistochemistry for demonstration of NOS activity in vivo and in vitro.

    PubMed

    Keilhoff, G; Reiser, M; Stanarius, A; Aoki, E; Wolf, G

    2000-08-01

    Nitric oxide (NO), a biomolecule with major cytotoxic potency, is generated by NO synthases (NOS) utilizing l-arginine as substrate and citrulline is formed as a "side product." In brain tissue, citrulline is considered to be produced exclusively by NOS, due to the incomplete urea cycle in the brain. We aimed to characterize NOS activity by citrulline immunostaining in different cell types of the brain under in situ conditions and in slice and culture experiments. NOS-positive neurons and activated microglial cells were the most prominent citrulline-positive structures. Lack of citrulline immunoreaction in neurons of nNOS knockout mice emphasizes the dependency of citrulline positivity on NOS activity, and likewise there was no citrulline staining after application of the NOS inhibitors 7-nitroindazole and NIL. Interestingly, only a portion of NOS-containing neurons costained for citrulline. The inhibition of argininosuccinate synthetase by alpha-methyl-dl-aspartate increased the number of citrulline-positive cells, apparently due to reduction of the turnover rate of citrulline. Cells positive for NOS but negative for citrulline may indicate that the enzyme is either not activated or inhibited by cellular control mechanisms. The fact that not all citrulline-positive cells were NOS positive may be explained by an insufficient detection sensitivity or by disparate sites of citrulline production and recycling. The present results show that citrulline immunocytochemistry offers a viable and convenient means for studying NOS activity at the single-cell level to elicit its posttranslational control under physiological and pathophysiological conditions. PMID:10944418

  1. Identification of citrullinated peptides in the synovial fluid of patients with rheumatoid arthritis using LC-MALDI-TOF/TOF.

    PubMed

    Wang, Fei; Chen, Fang-Fang; Gao, Wen-Bo; Wang, Hai-Yong; Zhao, Ning-Wei; Xu, Min; Gao, De-Yu; Yu, Wei; Yan, Xiao-Ling; Zhao, Jian-Ning; Li, Xiao-Jun

    2016-09-01

    The objective of the study is to investigate potential citrullinated autoantigens as targets of anti-citrullinated protein antibodies (ACPAs) response in synovial fluids (SFs) of patients with rheumatoid arthritis (RA). SFs from six RA patients and six osteoarthritis (OA) patients as controls were collected. The citrullinated proteins in SFs were extracted by immunoprecipitation with rabbit anti-citrulline antibodies. Matrix-assisted laser desorption/ionization time of flight mass spectrometry/time of flight mass spectrometry (MALDI-TOF/TOF) mass spectrometry was subsequently performed to discover a characteristic neutral loss to finally determine citrullinated autoantigens. A total of 182 citrullinated peptides and 200 citrullinated sites were identified in RA SFs, while 3 citrullinated peptides and 4 citrullinated sites were identified in OA SFs. The 182 citrullinated peptides from RA SFs and the 3 citrullinated peptides from OA SFs were derived from 83 and 3 autoantigens, respectively. Eighty-three autoantigens except protein-arginine deiminase type-2 (PADI2) and protein-arginine deiminase type-2 (PADI4) were over-citrullinated compared with controls, and the citrullinated sites of PADI2 and PADI4 were different in two groups. Interestingly, citrullinated histone H3.3 (H3F3A) was found in OA controls, but not in RA groups. The differential citrullinated proteins identified in RA SFs suggested potential autoantigens were targeted for ACPAs response and might contribute to the induction and perpetuation of complement activation and joint inflammation in RA. PMID:27060082

  2. Improvement of L-citrulline production in Corynebacterium glutamicum by ornithine acetyltransferase.

    PubMed

    Hao, N; Mu, J; Hu, N; Xu, S; Yan, M; Li, Y; Guo, K; Xu, L

    2015-02-01

    In this study, Corynebacterium glutamicum ATCC 13032 was engineered to produce L-citrulline through a metabolic engineering strategy. To prevent the flux away from L-citrulline and to increase the expression levels of genes involved in the citrulline biosynthesis pathway, the argininosuccinate synthase gene (argG) and the repressor gene (argR) were inactivated. The engineered C. glutamicum ATCC 13032 ∆argG ∆argR (CIT 2) produced higher amounts of L-citrulline (5.43 g/L) compared to the wildtype strain (0.15 g/L). To determine new strategies for further enhancement of L-citrulline production, the effect of L-citrulline on ornithine acetyltransferase (EC 2.3.1.35; OATase; ArgJ) was first investigated. Citrulline was determined to inhibit Ornithine acetyltransferase; for 50 % inhibition, citrulline concentration was 30 mM. The argJ gene from C. glutamicum ATCC 13032 was cloned, and the recombinant shuttle plasmid pXMJ19-argJ was constructed and expressed in C. glutamicum ATCC 13032 ∆argG ∆argR (CIT 2). Overexpression of the argJ gene exhibited increased OAT activity and resulted in a positive effect on citrulline production (8.51 g/L). These results indicate that OAT plays a vital role during L-citrulline production in C. glutamicum. PMID:25492493

  3. Organic anion transporter OAT1 is involved in renal handling of citrulline.

    PubMed

    Nakakariya, Masanori; Shima, Yoichiro; Shirasaka, Yoshiyuki; Mitsuoka, Keisuke; Nakanishi, Takeo; Tamai, Ikumi

    2009-07-01

    Because citrulline plasma concentration is elevated in kidney failure, citrulline could be a biomarker of renal insufficiency, although the mechanism regulating its disposition in the kidney has not been clarified. In rat kidney slices, citrulline uptake was apparently Na(+) dependent, saturable with K(m) 556 microM, and significantly inhibited by anionic (PAH) and cationic (TEA) compounds, but not by probenecid at 1 mM. Preincubation of kidney slices with glutarate increased citrulline uptake, while such an increase was not observed after preincubation of the slices in Na(+)-free buffer. This result suggested that a sodium-dependent dicarboxylate cotransporter is involved in citrulline uptake by rat kidney slices. In studies using transporter-overexpressing cells, human organic anion transporter 1 (OAT1) and rat Oat1 exhibited citrulline transport activity with K(m) values of 238 and 373 microM, respectively, while other OATs and organic cation transporters (OCTs) did not transport citrulline. Based on the relative activity factor method, the contribution of rat Oat1 to the overall uptake of citrulline in rat kidney slices was approximately 70%. Moreover, the interaction among citrulline, PAH, and probenecid uptakes via rat Oat1 suggested that there are multiple functional sites on Oat1 and that the citrulline site may be distinct from the PAH and probenecid site. Thus OAT1/Oat1 appears to be one of the major contributors to renal basolateral uptake of citrulline, and impaired activities of these transporters may contribute substantially to the increase in plasma citrulline in renal failure. Accordingly, citrulline may be useful for diagnosis of kidney function as is creatinine. PMID:19403644

  4. Arginine and Citrulline and the Immune Response in Sepsis

    PubMed Central

    Wijnands, Karolina A.P.; Castermans, Tessy M.R.; Hommen, Merel P.J.; Meesters, Dennis M.; Poeze, Martijn

    2015-01-01

    Arginine, a semi-essential amino acid is an important initiator of the immune response. Arginine serves as a precursor in several metabolic pathways in different organs. In the immune response, arginine metabolism and availability is determined by the nitric oxide synthases and the arginase enzymes, which convert arginine into nitric oxide (NO) and ornithine, respectively. Limitations in arginine availability during inflammatory conditions regulate macrophages and T-lymfocyte activation. Furthermore, over the past years more evidence has been gathered which showed that arginine and citrulline deficiencies may underlie the detrimental outcome of inflammatory conditions, such as sepsis and endotoxemia. Not only does the immune response contribute to the arginine deficiency, also the impaired arginine de novo synthesis in the kidney has a key role in the eventual observed arginine deficiency. The complex interplay between the immune response and the arginine-NO metabolism is further underscored by recent data of our group. In this review we give an overview of physiological arginine and citrulline metabolism and we address the experimental and clinical studies in which the arginine-citrulline NO pathway plays an essential role in the immune response, as initiator and therapeutic target. PMID:25699985

  5. L-citrulline immunostaining identifies nitric oxide production sites within neurons

    NASA Technical Reports Server (NTRS)

    Martinelli, G. P. T.; Friedrich, V. L. Jr; Holstein, G. R.

    2002-01-01

    The cellular and subcellular localization of L-citrulline was analyzed in the adult rat brain and compared with that of traditional markers for the presence of nitric oxide synthase. Light, transmission electron, and confocal laser scanning microscopy were used to study tissue sections processed for immunocytochemistry employing a monoclonal antibody against L-citrulline or polyclonal anti-neuronal nitric oxide synthase sera, and double immunofluorescence to detect neuronal nitric oxide synthase and L-citrulline co-localization. The results demonstrate that the same CNS regions and cell types are labeled by neuronal nitric oxide synthase polyclonal antisera and L-citrulline monoclonal antibodies, using both immunocytochemistry and immunofluorescence. Short-term pretreatment with a nitric oxide synthase inhibitor reduces L-citrulline immunostaining, but does not affect neuronal nitric oxide synthase immunoreactivity. In the vestibular brainstem, double immunofluorescence studies show that many, but not all, neuronal nitric oxide synthase-positive cells co-express L-citrulline, and that local intracellular patches of intense L-citrulline accumulation are present in some neurons. Conversely, all L-citrulline-labeled neurons co-express neuronal nitric oxide synthase. Cells expressing neuronal nitric oxide synthase alone are interpreted as neurons with the potential to produce nitric oxide under other stimulus conditions, and the subcellular foci of enhanced L-citrulline staining are viewed as intracellular sites of nitric oxide production. This interpretation is supported by ultrastructural observations of subcellular foci with enhanced L-citrulline and/or neuronal nitric oxide synthase staining that are located primarily at postsynaptic densities and portions of the endoplasmic reticulum. We conclude that nitric oxide is produced and released at focal sites within neurons that are identifiable using L-citrulline as a marker. Copyright 2002 IBRO.

  6. De novo synthesis is the main source of ornithine for citrulline production in neonatal pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrulline is an amino acid synthesized in the gut and utilized for the synthesis of the conditionally essential amino acid arginine. Recently, the origin of the ornithine utilized for citrulline synthesis has become a matter of discussion. Multiple physiological factors may have contributed to the ...

  7. Protein Citrullination: A Proposed Mechanism for Pathology in Traumatic Brain Injury

    PubMed Central

    Lazarus, Rachel C.; Buonora, John E.; Flora, Michael N.; Freedy, James G.; Holstein, Gay R.; Martinelli, Giorgio P.; Jacobowitz, David M.; Mueller, Gregory P.

    2015-01-01

    Protein citrullination is a calcium-driven post-translational modification proposed to play a causative role in the neurodegenerative disorders of Alzheimer’s disease, multiple sclerosis (MS), and prion disease. Citrullination can result in the formation of antigenic epitopes that underlie pathogenic autoimmune responses. This phenomenon, which is best understood in rheumatoid arthritis, may play a role in the chronic dysfunction following traumatic brain injury (TBI). Despite substantial evidence of aberrations in calcium signaling following TBI, there is little understanding of how TBI alters citrullination in the brain. The present investigation addressed this gap by examining the effects of TBI on the distribution of protein citrullination and on the specific cell types involved. Immunofluorescence revealed that controlled cortical impact in rats profoundly up-­regulated protein citrullination in the cerebral cortex, external capsule, and hippocampus. This response was exclusively seen in astrocytes; no such effects were observed on the status of protein citrullination in neurons, oligodendrocytes or microglia. Further, proteomic analyses demonstrated that the effects of TBI on citrullination were confined to a relatively small subset of neural proteins. Proteins most notably affected were those also reported to be citrullinated in other disorders, including prion disease and MS. In vivo findings were extended in an in vitro model of simulated TBI employing normal human astrocytes. Pharmacologically induced calcium excitotoxicity was shown to activate the citrullination and breakdown of glial fibrillary acidic protein, producing a novel candidate TBI biomarker and potential target for autoimmune recognition. In summary, these findings demonstrate that the effects of TBI on protein citrullination are selective with respect to brain region, cell type, and proteins modified, and may contribute to a role for autoimmune dysfunction in chronic pathology following

  8. Protein Citrullination: A Proposed Mechanism for Pathology in Traumatic Brain Injury.

    PubMed

    Lazarus, Rachel C; Buonora, John E; Flora, Michael N; Freedy, James G; Holstein, Gay R; Martinelli, Giorgio P; Jacobowitz, David M; Mueller, Gregory P

    2015-01-01

    Protein citrullination is a calcium-driven post-translational modification proposed to play a causative role in the neurodegenerative disorders of Alzheimer's disease, multiple sclerosis (MS), and prion disease. Citrullination can result in the formation of antigenic epitopes that underlie pathogenic autoimmune responses. This phenomenon, which is best understood in rheumatoid arthritis, may play a role in the chronic dysfunction following traumatic brain injury (TBI). Despite substantial evidence of aberrations in calcium signaling following TBI, there is little understanding of how TBI alters citrullination in the brain. The present investigation addressed this gap by examining the effects of TBI on the distribution of protein citrullination and on the specific cell types involved. Immunofluorescence revealed that controlled cortical impact in rats profoundly up--regulated protein citrullination in the cerebral cortex, external capsule, and hippocampus. This response was exclusively seen in astrocytes; no such effects were observed on the status of protein citrullination in neurons, oligodendrocytes or microglia. Further, proteomic analyses demonstrated that the effects of TBI on citrullination were confined to a relatively small subset of neural proteins. Proteins most notably affected were those also reported to be citrullinated in other disorders, including prion disease and MS. In vivo findings were extended in an in vitro model of simulated TBI employing normal human astrocytes. Pharmacologically induced calcium excitotoxicity was shown to activate the citrullination and breakdown of glial fibrillary acidic protein, producing a novel candidate TBI biomarker and potential target for autoimmune recognition. In summary, these findings demonstrate that the effects of TBI on protein citrullination are selective with respect to brain region, cell type, and proteins modified, and may contribute to a role for autoimmune dysfunction in chronic pathology following TBI

  9. Identification and quantitation of asparagine and citrulline using high-performance liquid chromatography (HPLC).

    PubMed

    Bai, Cheng; Reilly, Charles C; Wood, Bruce W

    2007-01-01

    High-performance liquid chromatography (HPLC) analysis was used for identification of two problematic ureides, asparagine and citrulline. We report here a technique that takes advantage of the predictable delay in retention time of the co-asparagine/citrulline peak to enable both qualitative and quantitative analysis of asparagine and citrulline using the Platinum EPS reverse-phase C18 column (Alltech Associates). Asparagine alone is eluted earlier than citrulline alone, but when both of them are present in biological samples they may co-elute. HPLC retention times for asparagine and citrulline were influenced by other ureides in the mixture. We found that at various asparagines and citrulline ratios [= 3:1, 1:1, and 1:3; corresponding to 75:25, 50:50, and 25:75 (microMol ml(-1)/microMol ml(-1))], the resulting peak exhibited different retention times. Adjustment of ureide ratios as internal standards enables peak identification and quantification. Both chemicals were quantified in xylem sap samples of pecan [Carya illinoinensis (Wangenh.) K. Koch] trees. Analysis revealed that tree nickel nutrition status affects relative concentrations of Urea Cycle intermediates, asparagine and citrulline, present in sap. Consequently, we concluded that the HPLC methods are presented to enable qualitative and quantitative analysis of these metabolically important ureides. PMID:19662174

  10. The effect of l-citrulline and watermelon juice supplementation on anaerobic and aerobic exercise performance.

    PubMed

    Cutrufello, Paul T; Gadomski, Stephen J; Zavorsky, Gerald S

    2015-01-01

    Citrulline has been proposed as an ergogenic aid, leading to an interest in watermelon given its high citrulline concentration. The aim of this study was to determine the effects of a single, pre-exercise dose of l-citrulline, watermelon juice, or a placebo on the total maximum number of repetitions completed over 5 sets, time to exhaustion, maximal oxygen consumption (VO2max), anaerobic threshold, and flow-mediated vasodilation. A randomised double-blind within-participants study design was used to examine these effects among 22 participants (n = 11 males). Supplementation included either a 7.5% sucrose drink containing 6 g of l-citrulline, 710 mL of watermelon juice (~1.0 g citrulline), or a 7.5% sucrose placebo drink. Supplementation was administered 1 or 2 h before exercise testing to investigate a timing effect. There was no significant effect between the three supplements for the total number of repetitions, time to exhaustion, VO2max, anaerobic threshold, or flow-mediated vasodilation. There was also no interaction observed relative to gender or supplement timing (P > 0.05). A single dose of l-citrulline or watermelon juice as a pre-exercise supplement appears to be ineffective in improving exercise performance; however, greater doses of l-citrulline have been shown to be safe and are currently left unexamined. PMID:25517106

  11. In the rat, citrullinated autologous fibrinogen is immunogenic but the induced autoimmune response is not arthritogenic

    PubMed Central

    Duplan, V; Foulquier, C; Clavel, C; Al Badine, R; Serre, G; Saoudi, A; Sebbag, M

    2006-01-01

    Conversion of arginyl to citrullyl residues (citrullination) is essential for the formation of the epitopes recognized by rheumatoid arthritis (RA)-associated autoantibodies to citrullinated proteins (ACPA). ACPA are secreted by plasma cells of the rheumatoid synovial tissue where their major target, citrullinated fibrin, is abundant. Although numerous arguments suggest that ACPA play an important role in RA, their pathological relevance remains to be established. In the present study, we assessed the immunogenicity and arthritogenicity of complete Freund's adjuvant-emulsified autologous citrullinated (C-rFBG) or non-citrullinated (NC-rFBG) fibrinogen in Lewis (LEW) and Brown–Norway rats, which exhibit drastic differences in their susceptibility to induced autoimmune diseases. NC-rFBG induced no antibody response. In contrast, a single injection of C-rFBG induced an IgG response directed mainly to citrullinated determinants of rFBG. However, all rat strains remained devoid of clinical and histological signs of arthritis up to 3 months after C-rFBG inoculation. Next, in LEW rats, we tested whether autoimmunity to C-rFBG could aggravate acute ankle arthritis triggered by intra-articular injection of incomplete Freund's adjuvant (IFA). However, such arthritis evolved identically in the presence or absence of anti-C-rFBG autoantibodies. However, IFA-injected joints were devoid of citrullinated fibrin deposits. Therefore, citrullination allows breakdown of immunological tolerance but the autoimmune response developed is not spontaneously arthritogenic. Whether or not it can aggravate arthritis with citrullinated fibrin deposits remains to be evaluated. PMID:16907920

  12. Citrulline as a Biomarker for Gastrointestinal-Acute Radiation Syndrome: Species Differences and Experimental Condition Effects.

    PubMed

    Bujold, K; Hauer-Jensen, M; Donini, O; Rumage, A; Hartman, D; Hendrickson, H P; Stamatopoulos, J; Naraghi, H; Pouliot, M; Ascah, A; Sebastian, M; Pugsley, M K; Wong, K; Authier, S

    2016-07-01

    Animal models of hematopoietic and gastrointestinal acute radiation syndromes (ARS) have been characterized to develop medical countermeasures. Acute radiation-induced decrease of intestinal absorptive function has been correlated to a decrease in the number of intestinal crypt cells resulting from apoptosis and enterocyte mass reduction. Citrulline, a noncoded amino acid, is produced almost exclusively by the enterocytes of the small intestine. Citrullinemia has been identified as a simple, sensitive and suitable biomarker for radiation-induced injury associated with gastrointestinal ARS (GI-ARS). Here we discuss the effect of radiation on plasma citrulline levels in three different species, C57BL/6 mice, Göttingen minipigs and rhesus nonhuman primates (NHPs), measured by liquid chromatography tandem mass spectrometry (LC-MS/MS). The effects of experimental study conditions such as feeding and anesthesia were also examined on plasma citrulline levels in the NHPs. Both the mice and Göttingen minipigs were partial-body irradiated (PBI) with doses from 13-17 Gy and 8-16 Gy, respectively, whereas NHPs were total-body irradiated (TBI) with doses from 6.72-13 Gy. Blood samples were taken at different time points and plasma citrulline levels were measured in the three species at baseline and after irradiation. Basal plasma citrulline concentrations (mean ± SEM) in mice and minipigs were 57.8 ± 2.8 μM and 63.1 ± 2.1 μM, respectively. NHPs showed a basal plasma citrulline concentration of 32.6 ± 0.7 μM, very similar to that of humans (∼40 μM). Plasma citrulline progressively decreased after irradiation, reaching nadir values between day 3.5 and 7. The onset of citrulline recovery was observed earlier at lower radiation doses, while only partial citrulline recovery was noted at higher radiation doses in minipigs and NHPs, complete recovery was noted in mice at all doses. Plasma citrulline levels in NHPs anesthetized with ketamine and acepromazine significantly

  13. Characterization and Localization of Citrullinated Proteoglycan Aggrecan in Human Articular Cartilage

    PubMed Central

    Glant, Tibor T.; Ocsko, Timea; Markovics, Adrienn; Szekanecz, Zoltan; Katz, Robert S.; Rauch, Tibor A.; Mikecz, Katalin

    2016-01-01

    Background Rheumatoid arthritis (RA) is an autoimmune disease of the synovial joints. The autoimmune character of RA is underscored by prominent production of autoantibodies such as those against IgG (rheumatoid factor), and a broad array of joint tissue-specific and other endogenous citrullinated proteins. Anti-citrullinated protein antibodies (ACPA) can be detected in the sera and synovial fluids of RA patients and ACPA seropositivity is one of the diagnostic criteria of RA. Studies have demonstrated that RA T cells respond to citrullinated peptides (epitopes) of proteoglycan (PG) aggrecan, which is one of the most abundant macromolecules of articular cartilage. However, it is not known if the PG molecule is citrullinated in vivo in human cartilage, and if so, whether citrulline-containing neoepitopes of PG (CitPG) can contribute to autoimmunity in RA. Methods CitPG was detected in human cartilage extracts using ACPA+ RA sera in dot blot and Western blot. Citrullination status of in vitro citrullinated recombinant G1 domain of human PG (rhG1) was confirmed by antibody-based and chemical methods, and potential sites of citrullination in rhG1 were explored by molecular modeling. CitPG-specific serum autoantibodies were quantified by enzyme-linked immunosorbent assays, and CitPG was localized in osteoarthritic (OA) and RA cartilage using immunohistochemistry. Findings Sera from ACPA+ RA patients reacted with PG purified from normal human cartilage specimens. PG fragments (mainly those containing the G1 domain) from OA or RA cartilage extracts were recognized by ACPA+ sera but not by serum from ACPA- individuals. ACPA+ sera also reacted with in vitro citrullinated rhG1 and G3 domain-containing fragment(s) of PG. Molecular modeling suggested multiple sites of potential citrullination within the G1 domain. The immunohistochemical localization of CitPG was different in OA and RA cartilage. Conclusions CitPG is a new member of citrullinated proteins identified in human

  14. Extensive Citrullination Promotes Immunogenicity of HSP90 through Protein Unfolding and Exposure of Cryptic Epitopes.

    PubMed

    Travers, Timothy S; Harlow, Lisa; Rosas, Ivan O; Gochuico, Bernadette R; Mikuls, Ted R; Bhattacharya, Sanjoy K; Camacho, Carlos J; Ascherman, Dana P

    2016-09-01

    Post-translational protein modifications such as citrullination have been linked to the breach of immune tolerance and clinical autoimmunity. Previous studies from our laboratory support this concept, demonstrating that autoantibodies targeting citrullinated isoforms of heat shock protein 90 (HSP90) are associated with rheumatoid arthritis complicated by interstitial lung disease. To further explore the relationship between citrullination and structural determinants of HSP90 immunogenicity, we employed a combination of ELISA-based epitope profiling, computational modeling, and mass-spectrometric sequencing of peptidylarginine deiminase (PAD)-modified protein. Remarkably, ELISAs involving selected citrullinated HSP90β/α peptides identified a key epitope corresponding to an internal Arg residue (R502 [HSP90β]/R510 [HSP90α]) that is normally buried within the crystal structure of native/unmodified HSP90. In vitro time/dose-response experiments reveal an ordered pattern of PAD-mediated deimination events culminating in citrullination of R502/R510. Conventional as well as scaled molecular dynamics simulations further demonstrate that citrullination of selected Arg residues leads to progressive disruption of HSP90 tertiary structure, promoting exposure of R502/R510 to PAD modification and subsequent autoantibody binding. Consistent with this process, ELISAs incorporating variably deiminated HSP90 as substrate Ag indicate a direct relationship between the degree of citrullination and the level of ex vivo Ab recognition. Overall, these data support a novel structural paradigm whereby citrullination-induced shifts in protein structure generate cryptic epitopes capable of bypassing B cell tolerance in the appropriate genetic context. PMID:27448590

  15. Induction of osteoclastogenesis and bone loss by human autoantibodies against citrullinated vimentin

    PubMed Central

    Harre, Ulrike; Georgess, Dan; Bang, Holger; Bozec, Aline; Axmann, Roland; Ossipova, Elena; Jakobsson, Per-Johan; Baum, Wolfgang; Nimmerjahn, Falk; Szarka, Eszter; Sarmay, Gabriella; Krumbholz, Grit; Neumann, Elena; Toes, Rene; Scherer, Hans-Ulrich; Catrina, Anca Irinel; Klareskog, Lars; Jurdic, Pierre; Schett, Georg

    2012-01-01

    Autoimmunity is complicated by bone loss. In human rheumatoid arthritis (RA), the most severe inflammatory joint disease, autoantibodies against citrullinated proteins are among the strongest risk factors for bone destruction. We therefore hypothesized that these autoantibodies directly influence bone metabolism. Here, we found a strong and specific association between autoantibodies against citrullinated proteins and serum markers for osteoclast-mediated bone resorption in RA patients. Moreover, human osteoclasts expressed enzymes eliciting protein citrullination, and specific N-terminal citrullination of vimentin was induced during osteoclast differentiation. Affinity-purified human autoantibodies against mutated citrullinated vimentin (MCV) not only bound to osteoclast surfaces, but also led to robust induction of osteoclastogenesis and bone-resorptive activity. Adoptive transfer of purified human MCV autoantibodies into mice induced osteopenia and increased osteoclastogenesis. This effect was based on the inducible release of TNF-α from osteoclast precursors and the subsequent increase of osteoclast precursor cell numbers with enhanced expression of activation and growth factor receptors. Our data thus suggest that autoantibody formation in response to citrullinated vimentin directly induces bone loss, providing a link between the adaptive immune system and bone. PMID:22505457

  16. Circadian and postprandial variation in plasma citrulline concentration in healthy dogs.

    PubMed

    Dahan, Julien M; Giron, Celine; Concordet, Didier; Dossin, Olivier

    2016-03-01

    OBJECTIVE To evaluate circadian and postprandial variations in plasma citrulline concentration in healthy dogs. ANIMALS 8 healthy Beagles. PROCEDURES Blood samples were collected from dogs after 12 hours of food withholding (0 hours; 8:00 am) and then every 2 hours for 12 hours (until 8:00 pm) and again at 24 hours (8:00 am the next day). The same protocol was repeated, with the only difference being that a meal was given immediately after the 0-hour sample collection point. Plasma citrulline concentration was measured by ion exchange chromatography. RESULTS No significant difference in plasma citrulline concentration was identified among measurement points when food was withheld. Mean ± SD plasma citrulline concentration at 4 hours (72.2 ± 12.7 μmol/L) and 24 hours (56.1 ± 12.5 μmol/L) after dogs were fed was significantly different from that at 0 hours (64.4 ± 12.7 μmol/L). CONCLUSIONS AND CLINICAL RELEVANCE Plasma citrulline concentration had no circadian variation in unfed dogs but increased significantly in fed dogs 4 hours after a meal. Therefore, food should be withheld from dogs for 8 to 12 hours before blood sample collection for measurement of citrulline concentration. PMID:26919600

  17. Citrulline Supplementation Improves Organ Perfusion and Arginine Availability under Conditions with Enhanced Arginase Activity

    PubMed Central

    Wijnands, Karolina A.P.; Meesters, Dennis M.; van Barneveld, Kevin W.Y.; Visschers, Ruben G.J.; Briedé, Jacob J.; Vandendriessche, Benjamin; van Eijk, Hans M.H.; Bessems, Babs A.F.M.; van den Hoven, Nadine; von Wintersdorff, Christian J.H.; Brouckaert, Peter; Bouvy, Nicole D.; Lamers, Wouter H.; Cauwels, Anje; Poeze, Martijn

    2015-01-01

    Enhanced arginase-induced arginine consumption is believed to play a key role in the pathogenesis of sickle cell disease-induced end organ failure. Enhancement of arginine availability with l-arginine supplementation exhibited less consistent results; however, l-citrulline, the precursor of l-arginine, may be a promising alternative. In this study, we determined the effects of l-citrulline compared to l-arginine supplementation on arginine-nitric oxide (NO) metabolism, arginine availability and microcirculation in a murine model with acutely-enhanced arginase activity. The effects were measured in six groups of mice (n = 8 each) injected intraperitoneally with sterile saline or arginase (1000 IE/mouse) with or without being separately injected with l-citrulline or l-arginine 1 h prior to assessment of the microcirculation with side stream dark-field (SDF)-imaging or in vivo NO-production with electron spin resonance (ESR) spectroscopy. Arginase injection caused a decrease in plasma and tissue arginine concentrations. l-arginine and l-citrulline supplementation both enhanced plasma and tissue arginine concentrations in arginase-injected mice. However, only the citrulline supplementation increased NO production and improved microcirculatory flow in arginase-injected mice. In conclusion, the present study provides for the first time in vivo experimental evidence that l-citrulline, and not l-arginine supplementation, improves the end organ microcirculation during conditions with acute arginase-induced arginine deficiency by increasing the NO concentration in tissues. PMID:26132994

  18. Citrullination of proteins: a common post-translational modification pathway induced by different nanoparticles in vitro and in vivo

    PubMed Central

    Mohamed, Bashir M; Verma, Navin K; Davies, Anthony M; McGowan, Aoife; Crosbie-Staunton, Kieran; Prina-Mello, Adriele; Kelleher, Dermot; Botting, Catherine H; Causey, Corey P; Thompson, Paul R; Pruijn, Ger JM; Kisin, Elena R; Tkach, Alexey V; Shvedova, Anna A; Volkov, Yuri

    2012-01-01

    Aim Rapidly expanding manufacture and use of nanomaterials emphasize the requirements for thorough assessment of health outcomes associated with novel applications. Post-translational protein modifications catalyzed by Ca2+-dependent peptidylargininedeiminases have been shown to trigger immune responses including autoantibody generation, a hallmark of immune complexes deposition in rheumatoid arthritis. Therefore, the aim of the study was to assess if nanoparticles are able to promote protein citrullination. Materials & methods Human A549 and THP-1 cells were exposed to silicon dioxide, carbon black or single-walled carbon nanotubes. C57BL/6 mice were exposed to respirable single-walled carbon nanotubes. Protein citrullination, peptidylargininedeiminases activity and target proteins were evaluated. Results The studied nanoparticles induced protein citrullination both in cultured human cells and mouse lung tissues. Citrullination occurred via the peptidylargininedeiminase-dependent mechanism. Cytokeratines 7, 8, 18 and plectins were identified as intracellular citrullination targets. Conclusion Nanoparticle exposure facilitated post-translational citrullination of proteins. PMID:22625207

  19. Combined whole-body vibration training and l-citrulline supplementation improves pressure wave reflection in obese postmenopausal women.

    PubMed

    Wong, Alexei; Alvarez-Alvarado, Stacey; Jaime, Salvador J; Kinsey, Amber W; Spicer, Maria T; Madzima, Takudzwa A; Figueroa, Arturo

    2016-03-01

    Postmenopausal women have increased wave reflection (augmentation pressure (AP) and index (AIx)) and reduced muscle function that predispose them to cardiac diseases and disability. Our aim was to examine the combined and independent effects of whole-body vibration training (WBVT) and l-citrulline supplementation on aortic hemodynamics and plasma nitric oxide metabolites (NOx) in postmenopausal women. Forty-one obese postmenopausal women were randomized to 3 groups: l-citrulline, WBVT+l-citrulline and WBVT+Placebo for 8 weeks. Brachial and aortic systolic blood pressure, diastolic blood pressure, AP, AIx, AIx adjusted to 75 beats/min (AIx@75), and NOx were measured before and after 8 weeks. All groups similarly decreased (P < 0.05) brachial and aortic pressures as well as AP, and similarly increased (P < 0.05) NOx levels. AIx and AIx@75 decreased (P < 0.01) in the WBVT+l-citrulline and WBVT+Placebo groups, but not in the l-citrulline group. The improvement in AIx@75 (-10.5% ± 8.8%, P < 0.05) in the WBVT+l-citrulline group was significant compared with the l-citrulline group. l-Citrulline supplementation and WBVT alone and combined decreased blood pressures. The combined intervention reduced AIx@75. This study supports the effectiveness of WBVT+l-citrulline as a potential intervention for prevention of hypertension-related cardiac diseases in obese postmenopausal women. PMID:26863234

  20. Citrulline increases cholesterol efflux from macrophages in vitro and ex vivo via ATP-binding cassette transporters

    PubMed Central

    Uto-Kondo, Harumi; Ayaori, Makoto; Nakaya, Kazuhiro; Takiguchi, Shunichi; Yakushiji, Emi; Ogura, Masatsune; Terao, Yoshio; Ozasa, Hideki; Sasaki, Makoto; Komatsu, Tomohiro; Sotherden, Grace Megumi; Hosoai, Tamaki; Sakurada, Masami; Ikewaki, Katsunori

    2014-01-01

    Reverse cholesterol transport (RCT) is a mechanism critical to the anti-atherogenic property of HDL. Although citrulline contributes to the amelioration of atherosclerosis via endothelial nitric oxide production, it remains unclear whether it affects RCT. This study was undertaken to clarify the effects of citrulline on expressions of specific transporters such as ATP binding cassette transporters (ABC)A1 and ABCG1, and the cholesterol efflux from macrophages to apolipoprotein (apo) A-I or HDL in vitro and ex vivo. Citrulline increased ABCA1 and ABCG1 mRNA and protein levels in THP-1 macrophages, translating into enhanced apoA-I- and HDL-mediated cholesterol efflux. In the human crossover study, 8 healthy male volunteers (age 30–49 years) consumed either 3.2 g/day citrulline or placebo for 1 week. Citrulline consumption brought about significant increases in plasma levels of citrulline and arginine. Supporting the in vitro data, monocyte-derived macrophages (MDM) differentiated under autologous post-citrulline sera demonstrated enhancement of both apoA-I- and HDL-mediated cholesterol efflux through increased ABCA1 and ABCG1 expressions, compared to MDM differentiated under pre-citrulline sera. However, the placebo did not modulate these parameters. Therefore, in addition to improving endothelium function, citrulline might have an anti-atherogenic property by increasing RCT of HDL. PMID:25120277

  1. L-citrulline supplementation reverses the impaired airway relaxation in neonatal rats exposed to hyperoxia

    PubMed Central

    2012-01-01

    Background Hyperoxia is shown to impair airway relaxation via limiting L-arginine bioavailability to nitric oxide synthase (NOS) and reducing NO production as a consequence. L-arginine can also be synthesized by L-citrulline recycling. The role of L-citrulline supplementation was investigated in the reversing of hyperoxia-induced impaired relaxation of rat tracheal smooth muscle (TSM). Methods Electrical field stimulation (EFS, 2–20 V)-induced relaxation was measured under in vitro conditions in preconstricted tracheal preparations obtained from 12 day old rat pups exposed to room air or hyperoxia (>95% oxygen) for 7 days supplemented with L-citrulline or saline (in vitro or in vivo). The role of the L-citrulline/L-arginine cycle under basal conditions was studied by incubation of preparations in the presence of argininosuccinate synthase (ASS) inhibitor [α-methyl-D, L-aspartate, 1 mM] or argininosuccinate lyase inhibitor (ASL) succinate (1 mM) and/or NOS inhibitor [Nω-nitro-L-arginine methyl ester; 100 μM] with respect to the presence or absence of L-citrulline (2 mM). Results Hyperoxia impaired the EFS-induced relaxation of TSM as compared to room air control (p < 0.001; 0.5 ± 0.1% at 2 V to 50.6 ± 5.7% at 20 V in hyperoxic group: 0.7 ± 0.2 at 2 V to 80.0 ± 5.6% at 20 V in room air group). Inhibition of ASS or ASL, and L-citrulline supplementation did not affect relaxation responses under basal conditions. However, inhibition of NOS significantly reduced relaxation responses (p < 0.001), which were restored to control level by L-citrulline. L-citrulline supplementation in vivo and in vitro also reversed the hyperoxia-impaired relaxation. The differences were significant (p <0.001; 0.8 ± 0.3% at 2 V to 47.1 ± 4.1% at 20 V without L-citrulline; 0.9 ± 0.3% at 2 V to 68.2 ± 4.8% at 20 V with L-citrulline). Inhibition of ASS or ASL prevented this effect of L-citrulline. Conclusion The

  2. Transport characteristics of L-citrulline in renal apical membrane of proximal tubular cells.

    PubMed

    Mitsuoka, Keisuke; Shirasaka, Yoshiyuki; Fukushi, Akimasa; Sato, Masanobu; Nakamura, Toshimichi; Nakanishi, Takeo; Tamai, Ikumi

    2009-04-01

    L-Citrulline has diagnostic potential for renal function, because its plasma concentration increases with the progression of renal failure. Although L-citrulline extracted by glomerular filtration in kidney is mostly reabsorbed, the mechanism involved is not clearly understood. The present study was designed to characterize L-citrulline transport across the apical membranes of renal epithelial tubular cells, using primary-cultured rat renal proximal tubular cells, as well as the human kidney proximal tubular cell line HK-2. L-Citrulline was transported in a Na(+)-dependent manner from the apical side of both cell types cultured on permeable supports with a microporous membrane. Kinetic analysis indicated that the transport involves two distinct Na(+)-dependent saturable systems and one Na(+)-independent saturable system in HK-2 cells. The uptake was competitively inhibited by neutral and cationic, but not anionic amino acids. Relatively large cationic and anionic compounds inhibited the uptake, but smaller ones did not. In HK-2 cells, mRNA expression of SLC6A19 and SLC7A9, which encode B(0)AT1 and b(0,+)AT, respectively, was detected by RT-PCR. In addition, L-citrulline transport was significantly decreased in HK-2 cells in which either SLC6A19 or SLC7A9 was silenced. Hence, these results suggest that amino acid transporters B(0)AT1 and b(0,+)AT are involved in the reabsorption of L-citrulline in the kidney, at least in part, by mediating the apical membrane transport of L-citrulline in renal tubule cells. PMID:19322909

  3. Application of synthetic peptides for detection of anti-citrullinated peptide antibodies.

    PubMed

    Trier, Nicole Hartwig; Holm, Bettina Eide; Slot, Ole; Locht, Henning; Lindegaard, Hanne; Svendsen, Anders; Nielsen, Christoffer Tandrup; Jacobsen, Søren; Theander, Elke; Houen, Gunnar

    2016-02-01

    Anti-citrullinated protein antibodies (ACPAs) are a hallmark of rheumatoid arthritis (RA) and represent an important tool for the serological diagnosis of RA. In this study, we describe ACPA reactivity to overlapping citrullinated Epstein-Barr virus nuclear antigen-1 (EBNA-1)-derived peptides and analyze their potential as substrates for ACPA detection by streptavidin capture enzyme-linked immunosorbent assay. Using systematically overlapping peptides, containing a 10 amino acid overlap, labelled with biotin C-terminally or N-terminally, sera from 160 individuals (RA sera (n=60), healthy controls (n=40), systemic lupus erythematosus (n=20), Sjögren's syndrome (n=40)) were screened for antibody reactivity. Antibodies to a panel of five citrullinated EBNA-1 peptides were found in 67% of RA sera, exclusively of the IgG isotype, while 53% of the patient sera reacted with a single peptide, ARGGSRERARGRGRG-Cit-GEKR, accounting for more than half of the ACPA reactivity alone. Moreover, these antibodies were detected in 10% of CCP2-negative RA sera. In addition, 47% of the RA sera reacted with two or three citrullinated EBNA-1 peptides from the selected peptide panel. Furthermore, a negative correlation between the biotin attachment site and the location of citrulline in the peptides was found, i.e. the closer the citrulline was located to biotin, the lower the antibody reactivity. Our data suggest that citrullinated EBNA-1 peptides may be considered a substrate for the detection of ACPAs and that the presence of Epstein-Barr virus may play a role in the induction of these autoantibodies. PMID:26796582

  4. Arginine behaviour after arginine or citrulline administration in older subjects.

    PubMed

    Moinard, C; Maccario, J; Walrand, S; Lasserre, V; Marc, J; Boirie, Y; Cynober, L

    2016-02-14

    Arginine (ARG) and its precursor citrulline (CIT) are popular dietary supplements, especially for the elderly. However, age-related reductions in lean body mass and alterations in organ functions could change their bioavailability. Pharmacokinetics and tolerance to amino acid (AA) loads are poorly documented in elderly subjects. The objective here was to characterise the plasma kinetics of CIT and ARG in a single-dosing study design. Eight fasting elderly men underwent two separate isomolar oral loading tests (10 g of CIT or 9·94 g of ARG). Blood was withdrawn over an 8-h period to measure plasma AA concentrations. Only CIT, ornithine and ARG plasma concentrations were changed. Volume of distribution was not dependent on AA administered. Conversely, parameters related to ARG kinetics were strongly dependent on AA administered: after ARG load, elimination was higher (ARG>CIT; P=0·041) and admission period+time at peak concentration was lower (ARG

  5. Citrullination of autoantigens implicates NETosis in the induction of autoimmunity.

    PubMed

    Dwivedi, Nishant; Radic, Marko

    2014-03-01

    Tolerance blocks the expression of autoantibodies, whereas autoimmunity promotes it. How tolerance breaks and autoantibody production begins thus are crucial questions for understanding and treatment of autoimmune diseases. Evidence implicates cell death and autoantigen modifications in the initiation of autoimmune reactions. One form of neutrophil cell death called NETosis deserves attention because it requires the post-translational modification of histones and results in the extracellular release of chromatin. NETosis received its name from NET, the acronym given to Neutrophil Extracellular Trap. The extracellular chromatin incorporates histones in which arginines have been converted to citrullines by peptidylarginine deiminase IV (PAD4). The deiminated chromatin may function to capture or 'trap' bacterial pathogens, thus generating an extracellular complex of deiminated histones and bacterial cell adjuvants. The complex of bacterial antigens and deiminated chromatin may be internalised by host phagocytes during acute inflammatory conditions, as arise during bacterial infections or chronic autoinflammatory disorders. The uptake and processing of deiminated chromatin together with bacterial adjuvants by phagocytes may induce the presentation of modified histone epitopes and co-stimulation, thus yielding a powerful stimulus to break tolerance. Autoantibodies to deiminated histones are prevalent in Felty's syndrome patients and are present in systemic lupus erythematosus (SLE) and patients with rheumatoid arthritis (RA). These observations clearly implicate histone deimination as an epigenetic mark that can act as an autoantibody stimulant. PMID:24291655

  6. Myelin Basic Protein Citrullination in Multiple Sclerosis: A Potential Therapeutic Target for the Pathology.

    PubMed

    Yang, Lei; Tan, Dewei; Piao, Hua

    2016-08-01

    Multiple sclerosis (MS) is a multifactorial demyelinating disease characterized by neurodegenerative events and autoimmune response against myelin component. Citrullination or deimination, a post-translational modification of protein-bound arginine into citrulline, catalyzed by Ca(2+) dependent peptidylarginine deiminase enzyme (PAD), plays an essential role in physiological processes include gene expression regulation, apoptosis and the plasticity of the central nervous system, while aberrant citrullination can generate new epitopes, thus involving in the initiation and/or progression of autoimmune disorder like MS. Myelin basic protein (MBP) is the major myelin protein and is generally considered to maintain the stability of the myelin sheath. This review describes the MBP citrullination and its consequence, as well as offering further support for the "inside-out" hypothesis that MS is primarily a neurodegenerative disease with secondary inflammatory demyelination. In addition, it discusses the role of MBP citrullination in the immune inflammation and explores the potential of inhibition of PAD enzymes as a therapeutic strategy for the disease. PMID:27097548

  7. Monoclonal L-citrulline immunostaining reveals nitric oxide-producing vestibular neurons

    NASA Technical Reports Server (NTRS)

    Holstein, G. R.; Friedrich, V. L. Jr; Martinelli, G. P.

    2001-01-01

    Nitric oxide is an unstable free radical that serves as a novel messenger molecule in the central nervous system (CNS). In order to understand the interplay between classic and novel chemical communication systems in vestibular pathways, the staining obtained using a monoclonal antibody directed against L-citrulline was compared with the labeling observed using more traditional markers for the presence of nitric oxide. Brainstem tissue from adult rats was processed for immunocytochemistry employing a monoclonal antibody directed against L-citrulline, a polyclonal antiserum against neuronal nitric oxide synthase, and/or NADPH-diaphorase histochemistry. Our findings demonstrate that L-citrulline can be fixed in situ by vascular perfusion, and can be visualized in fixed CNS tissue sections by immunocytochemistry. Further, the same vestibular regions and cell types are labeled by NADPH-diaphorase histochemistry, by the neuronal nitric oxide synthase antiserum, and by our anti-L-citrulline antibody. Clusters of L-citrulline-immunoreactive neurons are present in subregions of the vestibular nuclei, including the caudal portion of the inferior vestibular nucleus, the magnocellular portion of the medial vestibular nucleus, and the large cells in the ventral tier of the lateral vestibular nucleus. NADPH-diaphorase histochemical staining of these neurons clearly demonstrated their multipolar, fusiform and globular somata and long varicose dendritic processes. These results provide support for the suggestion that nitric oxide serves key roles in both vestibulo-autonomic and vestibulo-spinal pathways.

  8. Citrullination-acetylation interplay guides E2F-1 activity during the inflammatory response.

    PubMed

    Ghari, Fatemeh; Quirke, Anne-Marie; Munro, Shonagh; Kawalkowska, Joanna; Picaud, Sarah; McGouran, Joanna; Subramanian, Venkataraman; Muth, Aaron; Williams, Richard; Kessler, Benedikt; Thompson, Paul R; Fillipakopoulos, Panagis; Knapp, Stefan; Venables, Patrick J; La Thangue, Nicholas B

    2016-02-01

    Peptidyl arginine deiminase 4 (PAD4) is a nuclear enzyme that converts arginine residues to citrulline. Although increasingly implicated in inflammatory disease and cancer, the mechanism of action of PAD4 and its functionally relevant pathways remains unclear. E2F transcription factors are a family of master regulators that coordinate gene expression during cellular proliferation and diverse cell fates. We show that E2F-1 is citrullinated by PAD4 in inflammatory cells. Citrullination of E2F-1 assists its chromatin association, specifically to cytokine genes in granulocyte cells. Mechanistically, citrullination augments binding of the BET (bromodomain and extra-terminal domain) family bromodomain reader BRD4 (bromodomain-containing protein 4) to an acetylated domain in E2F-1, and PAD4 and BRD4 coexist with E2F-1 on cytokine gene promoters. Accordingly, the combined inhibition of PAD4 and BRD4 disrupts the chromatin-bound complex and suppresses cytokine gene expression. In the murine collagen-induced arthritis model, chromatin-bound E2F-1 in inflammatory cells and consequent cytokine expression are diminished upon small-molecule inhibition of PAD4 and BRD4, and the combined treatment is clinically efficacious in preventing disease progression. Our results shed light on a new transcription-based mechanism that mediates the inflammatory effect of PAD4 and establish the interplay between citrullination and acetylation in the control of E2F-1 as a regulatory interface for driving inflammatory gene expression. PMID:26989780

  9. The Prerequisites for Central Tolerance Induction against Citrullinated Proteins in the Mouse

    PubMed Central

    Engelmann, Robby; Biemelt, Andra; Cordshagen, Antje; Johl, Anja; Kuthning, Daniela; Müller-Hilke, Brigitte

    2016-01-01

    Objectives To assess the prerequisites for negative selection of peptidylcitrulline-specific T cells in the thymus. In detail, we here analyzed murine medullary thymic epithelial cells for the expression of peptidylarginine deiminases (PAD) and subsequent citrullination. Methods Medullary thymic epithelial cells were sorted, their mRNA was isolated and the expression of Pad genes was analyzed by quantitative PCR. Citrullination was detected by Western Blot in lysates of sorted medullary thymic epithelial cells and histologically by immunofluorescence of thymic thin sections. Results Pad2 and Pad4 are the main Pad isoforms expressed in mature medullary thymic epithelial cells of the mouse and their levels of expression are comparable to that of insulin (Ins2), another highly and promiscuously expressed protein in the thymus. Citrullination was detected in medullary thymic epithelial cells as shown by Western Blot and immunofluorescence. Conclusions Even though we here show that the murine thymus harbors the prerequisites for central tolerance to PAD and citrullinated peptides, it remains an open question whether the emergence of peptidylcitrulline-specific T cells and of autoantibodies recognizing citrullinated epitopes is caused by a failure of central or peripheral tolerance mechanisms. PMID:27362943

  10. Citrullination-acetylation interplay guides E2F-1 activity during the inflammatory response

    PubMed Central

    Ghari, Fatemeh; Quirke, Anne-Marie; Munro, Shonagh; Kawalkowska, Joanna; Picaud, Sarah; McGouran, Joanna; Subramanian, Venkataraman; Muth, Aaron; Williams, Richard; Kessler, Benedikt; Thompson, Paul R.; Fillipakopoulos, Panagis; Knapp, Stefan; Venables, Patrick J.; La Thangue, Nicholas B.

    2016-01-01

    Peptidyl arginine deiminase 4 (PAD4) is a nuclear enzyme that converts arginine residues to citrulline. Although increasingly implicated in inflammatory disease and cancer, the mechanism of action of PAD4 and its functionally relevant pathways remains unclear. E2F transcription factors are a family of master regulators that coordinate gene expression during cellular proliferation and diverse cell fates. We show that E2F-1 is citrullinated by PAD4 in inflammatory cells. Citrullination of E2F-1 assists its chromatin association, specifically to cytokine genes in granulocyte cells. Mechanistically, citrullination augments binding of the BET (bromodomain and extra-terminal domain) family bromodomain reader BRD4 (bromodomain-containing protein 4) to an acetylated domain in E2F-1, and PAD4 and BRD4 coexist with E2F-1 on cytokine gene promoters. Accordingly, the combined inhibition of PAD4 and BRD4 disrupts the chromatin-bound complex and suppresses cytokine gene expression. In the murine collagen-induced arthritis model, chromatin-bound E2F-1 in inflammatory cells and consequent cytokine expression are diminished upon small-molecule inhibition of PAD4 and BRD4, and the combined treatment is clinically efficacious in preventing disease progression. Our results shed light on a new transcription-based mechanism that mediates the inflammatory effect of PAD4 and establish the interplay between citrullination and acetylation in the control of E2F-1 as a regulatory interface for driving inflammatory gene expression. PMID:26989780

  11. Immune-mediated pore-forming pathways induce cellular hypercitrullination and generate citrullinated autoantigens in rheumatoid arthritis*

    PubMed Central

    Romero, Violeta; Fert-Bober, Justyna; Nigrovic, Peter A.; Darrah, Erika; Haque, Uzma J.; Lee, David M.; van Eyk, Jennifer; Rosen, Antony; Andrade, Felipe

    2014-01-01

    Autoantibodies to citrullinated protein antigens are specific markers of rheumatoid arthritis (RA). Although protein citrullination can be activated by numerous stimuli in cells, it remains unclear which of these produce the prominent citrullinated autoantigens targeted in RA. In these studies, we show that RA synovial fluid cells have an unusual pattern of citrullination with marked citrullination of proteins across the broad range of molecular weights, which we term cellular hypercitrullination. Although histone citrullination is a common event during neutrophil activation and death induced by different pathways including apoptosis, NETosis, and necroptosis/autophagy, hypercitrullination is not induced by these stimuli. However, marked hypercitrullination is induced by two immune-mediated membranolytic pathways, mediated by perforin and the membrane attack complex (MAC), which are active in the RA joint and of importance in RA pathogenesis. We further demonstrate that perforin and MAC activity on neutrophils generate the profile of citrullinated autoantigens characteristic of RA. These data suggest that activation of peptidylarginine deiminases during complement and perforin activity may be at the core of citrullinated autoantigen production in RA. These pathways may be amenable to monitoring and therapeutic modulation. PMID:24174326

  12. Relations among arginine, citrulline, ornithine, and leucine kinetics in adult burn patients.

    PubMed

    Yu, Y M; Ryan, C M; Burke, J F; Tompkins, R G; Young, V R

    1995-11-01

    Plasma fluxes of arginine, citrulline, and leucine, and the rate of conversion of labeled citrulline to arginine (Qcit-->arg) were determined in nine severely burned patients (mean: 56% body surface burn area, mean 10 d postinjury) while they received total parenteral nutrition (TPN) including an L-amino acid mixture that supplied a generous amount of nitrogen (mean: 0.39 +/- 0.02 g.kg-1.d-1). Plasma fluxes were also studied in these patients during a basal state (low-dose intravenous glucose) by using a primed, 4-h constant intravenous tracer-infusion protocol. Stable-nuclide labeled tracers were L-[15N-15N-guanidino,5,5,2H2]arginine; L-[13C-ureido]citrulline; L-[1-13C]leucine; and NaH13CO3 (prime only), with blood and expired air samples drawn at intervals to determine isotopic abundance of arginine, citrulline, ornithine, and alpha-ketoisocaproate (KIC; for leucine) in plasma and 13CO2 in breath. Leucine kinetics (flux and disappearance into protein synthesis) confirmed the anticipated higher protein turnover in these burn patients compared with healthy control subjects. The plasma arginine fluxes were correspondingly higher in burn patients than in healthy control subjects. However, the citrulline flux and rate of conversion of citrulline to arginine were not higher than values obtained in our laboratories in healthy adult subjects. We hypothesize that the higher rates of arginine loss from the body after burn injury would need to be balanced by an appropriate exogenous intake of preformed arginine to maintain protein homeostasis and promote recovery from this catabolic condition. PMID:7572742

  13. L-Citrulline dilates rat retinal arterioles via nitric oxide- and prostaglandin-dependent pathways in vivo.

    PubMed

    Mori, Asami; Morita, Masahiko; Morishita, Koji; Sakamoto, Kenji; Nakahara, Tsutomu; Ishii, Kunio

    2015-04-01

    L-Citrulline is an effective precursor of L-arginine produced by the L-citrulline/L-arginine cycle, and it exerts beneficial effects on the cardiovascular system by supporting enhanced nitric oxide (NO) production. NO dilates retinal blood vessels via the cyclooxygenase-mediated pathway. The purpose of this study was to examine the effects of L-citrulline on retinal circulation and to investigate the potential involvement of NO and prostaglandins in L-citrulline-induced responses in rats. L-Citrulline (10-300 μg kg(-1) min(-1), i.v.) increased the diameter of retinal arterioles without significantly changing mean blood pressure, heart rate, and fundus blood flow. The vasodilator response of retinal arterioles to l-citrulline was significantly diminished following treatment with N(G)-nitro-L-arginine methyl ester (30 mg/kg, i.v.), an NO synthase inhibitor, or indomethacin (5 mg/kg, i.v.), a cyclooxygenase inhibitor. In addition, α-methyl-dl-aspartic acid (147 mg/kg, i.v.), an inhibitor of argininosuccinate synthase, the rate-limiting enzyme for the recycling of l-citrulline to l-arginine, diminished the L-citrulline-induced retinal vasodilation. These results suggest that both NO- and prostaglandin-dependent pathways contribute to the L-citrulline-induced vasodilation of rat retinal arterioles. The L-citrulline/L-arginine recycling pathway may have more importance in regulating vascular tone in retinal blood vessels than in peripheral resistance vessels. PMID:25953269

  14. Autocitrullination of human peptidyl arginine deiminase type 4 regulates protein citrullination during cell activation

    PubMed Central

    Andrade, Felipe; Darrah, Erika; Gucek, Marjan; Cole, Robert N.; Rosen, Antony; Zhu, Xiaoming

    2010-01-01

    Objective To address mechanisms that control the activity of human peptidyl arginine deiminase type 4 (PAD-4). Methods PAD-4 autocitrullination was determined by anti–modified citrulline immunoblotting, using purified recombinant and endogenous PAD-4 from activated human primary neutrophils and cell lines expressing PAD-4. The citrullination sites in PAD-4 were determined by mass spectrometry. Mechanisms of autocitrullination-induced inactivation and the functional consequences of autocitrullination in PAD-4 polymorphic variants were addressed using purified components and cell lines expressing PAD-4 wild-type, PAD-4 mutant, and PAD-4 polymorphic variants relevant to rheumatoid arthritis (RA). Results PAD-4 is autocitrullinated in vitro and during activation of primary cells and cell lines expressing PAD-4. Interestingly, this modification inactivated the function of the enzyme. The efficiency of inactivation differed among genetically defined PAD-4 variants relevant to RA. PAD-4 was citrullinated at 10 sites, which are clustered into 3 distinct regions, including a cluster of arginines around the active site cleft where Arg-372 and -374 were identified as the potential autocitrullination targets that inactivate the enzyme. Autocitrullination also modified the structure of PAD-4, abrogating its recognition by multiple rabbit antibodies, but augmenting its recognition by human anti–PAD-4 autoantibodies. Conclusion Our findings suggest that autocitrullination regulates the production of citrullinated proteins during cell activation, and that this is affected by structural polymorphisms in PAD-4. Autocitrullination also influences PAD-4 structure and immune response. PMID:20201080

  15. HLA and anti-citrullinated protein antibodies: Building blocks in RA.

    PubMed

    van der Woude, Diane; Catrina, Anca I

    2015-12-01

    Antibodies against citrullinated proteins (ACPAs) are specific for rheumatoid arthritis (RA). ACPA-positive RA is a chronic inflammatory disease resulting from the complex interaction between genetic (mainly HLA class II genes) and environmental factors (mainly smoking). Recent findings have offered new insights into where, when and how anti-citrulline immunity develops. Some studies have found that a mucosal site, such as the lungs, may function as the initiating site for the immune response against citrullinated proteins, in line with the known association between smoking and ACPA. Other studies, focusing rather on the HLA associations, have suggested that cross-reactivity between microbial sequences and citrullinated self-proteins may lead to ACPA formation. Once ACPAs have developed, they can circulate throughout the body and upon reaching the joints exert direct pathogenic effects themselves. ACPAs can target first the bone compartment of the joints to activate osteoclasts and release interleukin (IL)-8 that in turn will promote bone loss and pain-like behaviour. In the current review, we will present the current understanding of the genetic associations in RA contributing to ACPA occurrence and offer insight in the latest findings explaining how and why autoimmunity generated in the lungs of genetically susceptible hosts might lead to chronic inflammation in the joints. PMID:27107507

  16. Purification and characterization of glutamate N-acetyltransferase involved in citrulline accumulation in wild watermelon.

    PubMed

    Takahara, Kentaro; Akashi, Kinya; Yokota, Akiho

    2005-10-01

    Citrulline is an efficient hydroxyl radical scavenger that can accumulate at concentrations of up to 30 mm in the leaves of wild watermelon during drought in the presence of strong light; however, the mechanism of this accumulation remains unclear. In this study, we characterized wild watermelon glutamate N-acetyltransferase (CLGAT) that catalyses the transacetylation reaction between acetylornithine and glutamate to form acetylglutamate and ornithine, thereby functioning in the first and fifth steps in citrulline biosynthesis. CLGAT enzyme purified 7000-fold from leaves was composed of two subunits with different N-terminal amino acid sequences. Analysis of the corresponding cDNA revealed that these two subunits have molecular masses of 21.3 and 23.5 kDa and are derived from a single precursor polypeptide, suggesting that the CLGAT precursor is cleaved autocatalytically at the conserved ATML motif, as in other glutamate N-acetyltransferases of microorganisms. A green fluorescence protein assay revealed that the first 26-amino acid sequence at the N-terminus of the precursor functions as a chloroplast transit peptide. The CLGAT exhibited thermostability up to 70 degrees C, suggesting an increase in enzyme activity under high leaf temperature conditions during drought/strong-light stresses. Moreover, CLGAT was not inhibited by citrulline or arginine at physiologically relevant high concentrations. These findings suggest that CLGAT can effectively participate in the biosynthesis of citrulline in wild watermelon leaves during drought/strong-light stress. PMID:16218965

  17. Arginine and ornithine are the main precursors for citrulline synthesis in mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent isotopic tracer studies in mice, piglets, and humans have produced conflicting results as to the main carbon skeleton precursor for citrulline and arginine synthesis. This may be due in part to the different tracers infused and models utilized to interpret the stable isotope data. Furthermore...

  18. L-citrulline levels in watermelon cultigens tested in two environments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Melon producers face increasing production costs and international market competition. Maximizing marketability of high quality watermelon [Citrullus lanatus (Thunb.) Matsum. and Nakai], that also contain high levels of the amino acid phytonutrient L-citrulline, can provide new market niches for th...

  19. Citrulline synthesis for endogenous arginine production is dependent on two distinct ornithine pools

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The endogenous synthesis of arginine (Arg) is a complex multi-organ process in which ornithine (Orn) is converted into citrulline (Cit) which is the immediate precursor for arginine synthesis. To investigate the origin of the Orn used for Cit (and thus Arg) production in mice, a series of primed-con...

  20. NETs are a source of citrullinated autoantigens and stimulate inflammatory responses in rheumatoid arthritis

    PubMed Central

    Khandpur, Ritika; Carmona-Rivera, Carmelo; Vivekanandan-Giri, Anuradha; Gizinski, Alison; Yalavarthi, Srilakshmi; Knight, Jason S.; Friday, Sean; Li, Sam; Patel, Rajiv M.; Subramanian, Venkataraman; Thompson, Paul; Chen, Pojen; Fox, David A.; Pennathur, Subramaniam; Kaplan, Mariana J.

    2013-01-01

    The early events leading to the development of rheumatoid arthritis (RA) remain unclear but formation of autoantibodies to citrullinated antigens (ACPA) is considered a key pathogenic phenomenon. Neutrophils isolated from patients with various autoimmune diseases display enhanced extracellular trap formation (NETs), a phenomenon that externalizes autoantigens and immunostimulatory molecules. We investigated whether aberrant NETosis occurs in RA, determined its triggers and examined its deleterious inflammatory consequences. Enhanced NETosis was observed in circulating and synovial fluid RA neutrophils, compared to neutrophils from healthy controls and from patients with osteoarthritis. Further, netting neutrophils infiltrated RA synovial tissue, rheumatoid nodules and skin. NETosis correlated with ACPA presence and levels and with systemic inflammatory markers. RA sera and immunoglobulin fractions from RA patients with high levels of ACPA and/or rheumatoid factor significantly enhanced NETosis, and the NETs induced by these autoantibodies displayed distinct protein content. During NETosis, neutrophils externalized citrullinated autoantigens implicated in RA pathogenesis, whereas anti-citrullinated vimentin antibodies potently induced NET formation. The inflammatory cytokines IL-17A and TNF-α induced NETosis in RA neutrophils. In turn, NETs significantly augmented inflammatory responses in RA and OA synovial fibroblasts, including induction of IL-6, IL-8, chemokines and adhesion molecules. These observations implicate accelerated NETosis in RA pathogenesis, through externalization of citrullinated autoantigens and immunostimulatory molecules that may promote aberrant adaptive and innate immune responses in the joint and in the periphery, and perpetuate pathogenic mechanisms in this disease. PMID:23536012

  1. Oral citrulline as arginine precursor may be beneficial in sickle cell disease: early phase two results.

    PubMed Central

    Waugh, W. H.; Daeschner, C. W.; Files, B. A.; McConnell, M. E.; Strandjord, S. E.

    2001-01-01

    L-Arginine may be a conditionally essential amino acid in children and adolescents with sickle cell disease, particularly as required substrate in the arginine-nitric oxide pathway for endogenous nitrovasodilation and vasoprotection. Vasoprotection by arginine is mediated partly by nitric oxide-induced inhibition of endothelial damage and inhibition of adhesion and activation of leukocytes. Activated leukocytes may trigger many of the complications, including vasoocclusive events and intimal hyperplasias. High blood leukocyte counts during steady states in the absence of infection are significant laboratory risk factors for adverse complications. L-Citrulline as precursor amino acid was given orally twice daily in daily doses of approximately 0.1 g/kg in a pilot Phase II clinical trial during steady states in four homozygous sickle cell disease subjects and one sickle cell-hemoglobin C disease patient (ages 10-18). There soon resulted dramatic improvements in symptoms of well-being, raised plasma arginine levels, and reductions in high total leukocyte and high segmented neutrophil counts toward or to within normal limits. Continued L-citrulline supplementation in compliant subjects continued to lessen symptomatology, to maintain plasma arginine concentrations greater than control levels, and to maintain nearly normal total leukocyte and neutrophil counts. Side effects or toxicity from citrulline were not experienced. Oral L-citrulline may portend very useful for palliative therapy in sickle cell disease. Placebo-controlled, long-term trials are now indicated. PMID:11688916

  2. Plasma citrulline level as a biomarker for cancer therapy-induced small bowel mucosal damage.

    PubMed

    Barzał, Justyna A; Szczylik, Cezary; Rzepecki, Piotr; Jaworska, Małgorzata; Anuszewska, Elżbieta

    2014-01-01

    Regimen-related mucosal toxicity is extremely common following cytotoxic chemotherapy and radiotherapy. Mucositis is as an important determinant of the inflammatory response and infectious complications in cancer treated patients. Most assessment scales for mucosal damage are focussed on oral mucositis, since it is easy to evaluate. Measuring gastrointestinal musocal damage objectively remains difficult because it cannot be seen directly or readily detected. One of potential non-invasive biomarkers of gastrointestinal mucosal damage is plasma citrulline level. Citrulline is an amino acid produced by small bowel enterocytes. Low concentration of free circulating citrulline signifies severe intestinal mucosal damage in humans with nonmalignant disorders, such as villous atrophy-associated diseases, short bowel syndrome, Crohn's disease, and is used in follow-up after small bowel transplantation. The plasma citrulline level is a reliable and objective biochemical marker of enterocyte mass and function in humans, and therefore can be used to monitor enterocyte toxicity resulting from chemotherapy and radiotherapy during anticancer therapy in patients with severely disturbed gut integrity. PMID:25473654

  3. Precursors for the synthesis of citrulline in mice fed arginine free diets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dietary arginine (Arg) is the main dietary precursor for citrulline (Cit) synthesis. To test the hypothesis that the contribution of dietary proline (Pro) and glutamine (Gln) increases during the feeding of an Arg free diet, rates of appearance (Ra) and precursor-intermediate-product relationships w...

  4. Glutamine supplementation, citrulline production, and de novo arginine synthesis: Is there a relation?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We would like to comment on the recent publications by Buijs et al. The authors hypothesized that a parenteral supplement of glutamine stimulates citrulline formation and enhances de novo arginine synthesis. To test this hypothesis, they conducted an experiment with stable isotopes in patients under...

  5. Quantification of L-Citrulline and other physiologic amino acids in watermelon and selected cucurbits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High performance liquid chromatography of dabsyl derivatives of amino acids was employed for quantification of physiologic amino acids in cucurbits. This method is particularly useful because the dabsyl derivatives of glutamine and citrulline are sufficiently separated to allow quantification of ea...

  6. Citrullinated glucose-regulated protein 78 is an autoantigen in type 1 diabetes.

    PubMed

    Rondas, Dieter; Crèvecoeur, Inne; D'Hertog, Wannes; Ferreira, Gabriela Bomfim; Staes, An; Garg, Abhishek D; Eizirik, Decio L; Agostinis, Patrizia; Gevaert, Kris; Overbergh, Lut; Mathieu, Chantal

    2015-02-01

    Posttranslational modifications of self-proteins play a substantial role in the initiation or propagation of the autoimmune attack in several autoimmune diseases, but their contribution to type 1 diabetes is only recently emerging. In the current study, we demonstrate that inflammatory stress, induced by the cytokines interleukin-1β and interferon-γ, leads to citrullination of GRP78 in β-cells. This is coupled with translocation of this endoplasmic reticulum chaperone to the β-cell plasma membrane and subsequent secretion. Importantly, expression and activity of peptidylarginine deiminase 2, one of the five enzymes responsible for citrullination and a candidate gene for type 1 diabetes in mice, is increased in islets from diabetes-prone nonobese diabetic (NOD) mice. Finally, (pre)diabetic NOD mice have autoantibodies and effector T cells that react against citrullinated GRP78, indicating that inflammation-induced citrullination of GRP78 in β-cells generates a novel autoantigen in type 1 diabetes, opening new avenues for biomarker development and therapeutic intervention. PMID:25204978

  7. L-Citrulline Protects Skeletal Muscle Cells from Cachectic Stimuli through an iNOS-Dependent Mechanism

    PubMed Central

    Ham, Daniel J.; Gleeson, Benjamin G.; Chee, Annabel; Baum, Dale M.; Caldow, Marissa K.; Lynch, Gordon S.; Koopman, René

    2015-01-01

    Dietary L-citrulline is thought to modulate muscle protein turnover by increasing L-arginine availability. To date, the direct effects of increased L-citrulline concentrations in muscle have been completely neglected. Therefore, we determined the role of L-citrulline in regulating cell size during catabolic conditions by depriving mature C2C12 myotubes of growth factors (serum free; SF) or growth factors and nutrients (HEPES buffered saline; HBS). Cells were treated with L-citrulline or equimolar concentrations of L-arginine (positive control) or L-alanine (negative control) and changes in cell size and protein turnover were assessed. In myotubes incubated in HBS or SF media, L-citrulline improved rates of protein synthesis (HBS: +63%, SF: +37%) and myotube diameter (HBS: +18%, SF: +29%). L-citrulline treatment substantially increased iNOS mRNA expression (SF: 350%, HBS: 750%). The general NOS inhibitor L-NAME and the iNOS specific inhibitor aminoguanidine prevented these effects in both models. Depriving myotubes in SF media of L-arginine or L-leucine, exacerbated wasting which was not attenuated by L-citrulline. The increased iNOS mRNA expression was temporally associated with increases in mRNA of the endogenous antioxidants SOD1, SOD3 and catalase. Furthermore, L-citrulline prevented inflammation (LPS) and oxidative stress (H2O2) induced muscle cell wasting. In conclusion, we demonstrate a novel direct protective effect of L-citrulline on skeletal muscle cell size independent of L-arginine that is mediated through induction of the inducible NOS (iNOS) isoform. This discovery of a nutritional modulator of iNOS mRNA expression in skeletal muscle cells could have substantial implications for the treatment of muscle wasting conditions. PMID:26513461

  8. Increased Plasma Citrulline in Mice Marks Diet-Induced Obesity and May Predict the Development of the Metabolic Syndrome

    PubMed Central

    Sailer, Manuela; Dahlhoff, Christoph; Giesbertz, Pieter; Eidens, Mena K.; de Wit, Nicole; Rubio-Aliaga, Isabel; Boekschoten, Mark V.; Müller, Michael; Daniel, Hannelore

    2013-01-01

    In humans, plasma amino acid concentrations of branched-chain amino acids (BCAA) and aromatic amino acids (AAA) increase in states of obesity, insulin resistance and diabetes. We here assessed whether these putative biomarkers can also be identified in two different obesity and diabetic mouse models. C57BL/6 mice with diet-induced obesity (DIO) mimic the metabolic impairments of obesity in humans characterized by hyperglycemia, hyperinsulinemia and hepatic triglyceride accumulation. Mice treated with streptozotocin (STZ) to induce insulin deficiency were used as a type 1 diabetes model. Plasma amino acid profiling of two high fat (HF) feeding trials revealed that citrulline and ornithine concentrations are elevated in obese mice, while systemic arginine bioavailability (ratio of plasma arginine to ornithine + citrulline) is reduced. In skeletal muscle, HF feeding induced a reduction of arginine levels while citrulline levels were elevated. However, arginine or citrulline remained unchanged in their key metabolic organs, intestine and kidney. Moreover, the intestinal conversion of labeled arginine to ornithine and citrulline in vitro remained unaffected by HF feeding excluding the intestine as prime site of these alterations. In liver, citrulline is mainly derived from ornithine in the urea cycle and DIO mice displayed reduced hepatic ornithine levels. Since both amino acids share an antiport mechanism for mitochondrial import and export, elevated plasma citrulline may indicate impaired hepatic amino acid handling in DIO mice. In the insulin deficient mice, plasma citrulline and ornithine levels also increased and additionally these animals displayed elevated BCAA and AAA levels like insulin resistant and diabetic patients. Therefore, type 1 diabetic mice but not DIO mice show the “diabetic fingerprint” of plasma amino acid changes observed in humans. Additionally, citrulline may serve as an early indicator of the obesity-dependent metabolic impairments. PMID

  9. Clinical applications of autoimmunity to citrullinated proteins in rheumatoid arthritis, from improving diagnostics to future therapies.

    PubMed

    Kinloch, Andrew J; Ng, Karen; Wright, Graham P

    2011-05-01

    Rheumatoid arthritis (RA), although widely considered to be the most commonly occurring autoimmune disease, has only truly been substantiated as a distinct autoimmune disease very recently. The lack of understanding of the specific autoimmune system/s at work in rheumatoid patients resulted in an absence of robust diagnostic tools and had meant that the rational choice for use and design of therapy was based on broad-spectrum immunosuppression. The revelation that the autoimmune response specific for patients with RA is to particular protein antigens bearing the post-translational modification 'citrulline' has therefore revolutionized diagnostics and has helped explain why patients carrying particular MHC alleles are predisposed to the disease. The last two decades have seen the characterization of citrullinated antigens targeted by both antibodies and T cells in rheumatoid patients. In more recent years, we have also witnessed the success of biological therapies in the treatment of RA that specifically target T cells and B cells. Ongoing mapping of antibody targets is increasing the percentage of patients who can be definitively diagnosed with, and prognosed to develop, RA. These advances have led to a great number of patents for citrullinated peptides that have been and may be, in the coming years, used in diagnostic test kits. More recently, characterization of T cell targets (citrullinated peptides) has resulted in the patenting of peptides that could be used in antigen specific therapy. This review focuses on the characterization of the autoimmune response to citrullinated protein targets in RA and how the community is translating this knowledge to improve diagnostics, prognostics and therapy. PMID:21453269

  10. Effect of level of dietary protein on arginine-stimulated citrulline synthesis. Correlation with mitochondrial N-acetylglutamate concentrations.

    PubMed Central

    Morimoto, B H; Brady, J F; Atkinson, D E

    1990-01-01

    Increases in dietary protein have been reported to increase the rate of citrulline synthesis and the level of N-acetylglutamate in liver. We have confirmed this effect of diet on citrulline synthesis in rat liver mitochondria and show parallel increases in N-acetylglutamate concentration. The magnitude of the effect of arginine in the suspending medium on citrulline synthesis was also dependent on dietary protein content. Mitochondria from rats fed on a protein-free diet initially contained low levels of N-acetylglutamate, and addition of arginine increased the rate of its synthesis. Citrulline synthesis and acetylglutamate content in these mitochondria increased more than 5-fold when 1 mM-arginine was added. A diet high in protein results in mitochondria with increased N-acetylglutamate and a high rate of citrulline synthesis; 1 mM-arginine increased citrulline synthesis in such mitochondria by only 36%. The concentration of arginine in portal blood was 47 microM in rats fed on a diet lacking protein, and 182 microM in rats fed on a diet containing 60% protein, suggesting that arginine may be a regulatory signal to the liver concerning the dietary protein intake. The rates of citrulline synthesis were proportional to the mitochondrial content of acetylglutamate in mitochondria obtained from rats fed on diets containing 0, 24, or 60% protein, whether incubated in the absence or presence of arginine. Although the effector concentrations are higher than the Ka for the enzymes, these results support the view that concentrations of both arginine and acetylglutamate are important in the regulation of synthesis of citrulline and urea. Additionally, the effects of dietary protein level (and of arginine) are exerted in large part by way of modulation of the concentration of acetylglutamate. PMID:2268294

  11. Discovery of peptidylarginine deiminase-4 substrates by protein array: antagonistic citrullination and methylation of human ribosomal protein S2.

    PubMed

    Guo, Qin; Bedford, Mark T; Fast, Walter

    2011-07-01

    Peptidylarginine deiminase (PAD) catalyzes the posttranslational citrullination of selected proteins in a calcium dependent manner. The PAD4 isoform has been implicated in multiple sclerosis, rheumatoid arthritis, some types of cancer, and plays a role in gene regulation. However, the substrate selectivity of PAD4 is not well defined, nor is the impact of citrullination on many other pathways. Here, a high-density protein array is used as a primary screen to identify 40 previously unreported PAD4 substrates, 10 of which are selected and verified in a cell lysate-based secondary assay. One of the most prominent hits, human 40S ribosomal protein S2 (RPS2), is characterized in detail. PAD4 citrullinates the Arg-Gly repeat region of RPS2, which is also an established site for Arg methylation by protein arginine methyltransferase 3 (PRMT3). As in other systems, crosstalk is observed; citrullination and methylation modifications are found to be antagonistic to each other, suggesting a conserved posttranslational regulatory strategy. Both PAD4 and PRMT3 are found to co-sediment with the free 40S ribosomal subunit fraction from cell extracts. These findings are consistent with participation of citrullination in the regulation of RPS2 and ribosome assembly. This application of protein arrays to reveal new PAD4 substrates suggests a role for citrullination in a number of different cellular pathways. PMID:21584310

  12. Serum metabolomics identifies citrulline as a predictor of adverse outcomes in an equine model of gut-derived sepsis.

    PubMed

    Steelman, Samantha M; Johnson, Philip; Jackson, Amy; Schulze, James; Chowdhary, Bhanu P

    2014-05-15

    Acute laminitis is an inflammatory disease of the equine foot that often occurs secondarily to sepsis or systemic inflammation associated with gastrointestinal disease. It has been suggested that laminitis is similar to multiple organ dysfunction syndrome in humans, although in horses the weight-bearing laminar epithelium of the foot appears to be the tissue most sensitive to insult and the first "organ" to fail. Metabolomics performed on serum samples collected before (Con) and after (Lmn) experimental induction of gastrointestinal-associated sepsis in six horses detected 1,177 metabolites of both mammalian and bacterial origin in equine serum. Network and correlation analyses suggested a dysregulation of fatty acid metabolism in the Lmn group, as well as an accumulation of organic acids such as lactate. Furthermore, concentrations of the amino acid citrulline were decreased in Lmn samples from all study animals, suggesting that citrulline might be useful as a biomarker to identify critically ill animals that are at risk of developing laminitis. We therefore established normal ranges of plasma citrulline concentrations in a separate group of horses (n = 36) and tested the ability of citrulline to predict adverse outcomes (laminitis or death) in critically ill horses (n = 23). Plasma citrulline was significantly lower in critically ill horses that went on to experience adverse outcomes (n = 6). Further study is required to accurately determine a diagnostic cutoff, but the present data are suggestive of the predictive value of citrulline as a biomarker for laminar failure in equine sepsis. PMID:24619519

  13. Citrullinated peptide dendritic cell immunotherapy in HLA risk genotype-positive rheumatoid arthritis patients.

    PubMed

    Benham, Helen; Nel, Hendrik J; Law, Soi Cheng; Mehdi, Ahmed M; Street, Shayna; Ramnoruth, Nishta; Pahau, Helen; Lee, Bernett T; Ng, Jennifer; Brunck, Marion E G; Hyde, Claire; Trouw, Leendert A; Dudek, Nadine L; Purcell, Anthony W; O'Sullivan, Brendan J; Connolly, John E; Paul, Sanjoy K; Lê Cao, Kim-Anh; Thomas, Ranjeny

    2015-06-01

    In animals, immunomodulatory dendritic cells (DCs) exposed to autoantigen can suppress experimental arthritis in an antigen-specific manner. In rheumatoid arthritis (RA), disease-specific anti-citrullinated peptide autoantibodies (ACPA or anti-CCP) are found in the serum of about 70% of RA patients and are strongly associated with HLA-DRB1 risk alleles. This study aimed to explore the safety and biological and clinical effects of autologous DCs modified with a nuclear factor κB (NF-κB) inhibitor exposed to four citrullinated peptide antigens, designated "Rheumavax," in a single-center, open-labeled, first-in-human phase 1 trial. Rheumavax was administered once intradermally at two progressive dose levels to 18 human leukocyte antigen (HLA) risk genotype-positive RA patients with citrullinated peptide-specific autoimmunity. Sixteen RA patients served as controls. Rheumavax was well tolerated: adverse events were grade 1 (of 4) severity. At 1 month after treatment, we observed a reduction in effector T cells and an increased ratio of regulatory to effector T cells; a reduction in serum interleukin-15 (IL-15), IL-29, CX3CL1, and CXCL11; and reduced T cell IL-6 responses to vimentin(447-455)-Cit450 relative to controls. Rheumavax did not induce disease flares in patients recruited with minimal disease activity, and DAS28 decreased within 1 month in Rheumavax-treated patients with active disease. This exploratory study demonstrates safety and biological activity of a single intradermal injection of autologous modified DCs exposed to citrullinated peptides, and provides rationale for further studies to assess clinical efficacy and antigen-specific effects of autoantigen immunomodulatory therapy in RA. PMID:26041704

  14. Diabetic nephropathy is resistant to oral L-arginine or L-citrulline supplementation.

    PubMed

    You, Hanning; Gao, Ting; Cooper, Timothy K; Morris, Sidney M; Awad, Alaa S

    2014-12-01

    Our recent publication showed that pharmacological blockade of arginases confers kidney protection in diabetic nephropathy via a nitric oxide (NO) synthase (NOS)3-dependent mechanism. Arginase competes with endothelial NOS (eNOS) for the common substrate L-arginine. Lack of L-arginine results in reduced NO production and eNOS uncoupling, which lead to endothelial dysfunction. Therefore, we hypothesized that L-arginine or L-citrulline supplementation would ameliorate diabetic nephropathy. DBA mice injected with multiple low doses of vehicle or streptozotocin (50 mg/kg ip for 5 days) were provided drinking water with or without L-arginine (1.5%, 6.05 g·kg(-1)·day(-1)) or L-citrulline (1.66%, 5.73 g·kg(-1)·day(-1)) for 9 wk. Nonsupplemented diabetic mice showed significant increases in albuminuria, blood urea nitrogen, glomerular histopathological changes, kidney macrophage recruitment, kidney TNF-α and fibronectin mRNA expression, kidney arginase activity, kidney arginase-2 protein expression, and urinary oxidative stress along with a significant reduction of nephrin and eNOS protein expression and kidney nitrite + nitrate compared with normal mice after 9 wk of diabetes. Surprisingly, L-arginine or L-citrulline supplementation in diabetic mice did not affect any of these parameters despite greatly increasing kidney and plasma arginine levels. These findings demonstrate that chronic L-arginine or L-citrulline supplementation does not prevent or reduce renal injury in a model of type 1 diabetes. PMID:25320354

  15. Evaluation of anti-citrullinated filaggrin antibodies as hallmarks for the diagnosis of rheumatic diseases

    PubMed Central

    Dubucquoi, S; Solau-Gervais, E; Lefranc, D; Marguerie, L; Sibilia, J; Goetz, J; Dutoit, V; Fauchais, A; Hachulla, E; Flipo, R; Prin, L

    2004-01-01

    Background: Anti-filaggrin antibodies (AFA) are among the most specific antibodies for rheumatoid arthritis, so procedures for their detection should be included in early biological diagnoses. AFA can be detected by indirect immunofluorescence (anti-keratin antibodies, AKA) or by new enzyme immunoassays (EIA). Their comparative performance needs to be established. Objective: To compare these technical procedures to optimise the serological diagnosis of rheumatoid arthritis. Methods: Results obtained using AKA and EIA were compared in 271 sera from 140 patients with rheumatoid arthritis at various stages, 98 patients with other autoimmune diseases, and 33 healthy subjects. EIA were successively undertaken with citrullinated linear filaggrin peptide (home made EIA) or cyclic citrullinated peptide (CCP2, commercial kits). Rheumatoid factor (RF) was assessed by EIA in all patients. Results: Anti-CCP2 kits showed the best sensitivity and specificity (65% and 96%, respectively). Among the 140 patients with rheumatoid arthritis, those with very recent disease (less than six months' duration, n = 21) were studied as a separate group. In this group, the sensitivity of anti-CCP2 kits decreased to ~50%. Nevertheless this assay remained the most accurate when compared with AKA or home made EIA using linear filaggrin peptides. The combination of anti-CCP2 and RF only slightly increased the sensitivity of the diagnosis of very early rheumatoid arthritis. Conclusions: Kits using citrullinated cyclic peptides (CCP2) were more suitable than either AKA or EIA using linear filaggrin peptides for the diagnosis of early rheumatoid disease. PMID:15020336

  16. Does Citrulline Have Protective Effects on Liver Injury in Septic Rats?

    PubMed Central

    Cai, Bin; Luo, Yu-long; Wang, Shi-jun; Wei, Wei-yuan; Zhang, Xue-hui; Huang, Wei; Li, Tong; Zhang, Meng; Wu, Nan; Roodrajeetsing, Gopaul; Zhang, Sen

    2016-01-01

    Citrulline (Cit) supplementation was proposed to serve as a therapeutic intervention to restore arginine (Arg) concentrations and improve related functions in sepsis. This study explored whether citrulline had positive effects on liver injury and cytokine release in the early stages of sepsis. The cecal ligation and puncture (CLP) model was utilized in our study. Rats were divided into four groups: normal, Cit, CLP, and CLP+Cit. The CLP group and CLP+Cit group were separated into 6-, 12-, and 24-hour groups, according to the time points of sacrifice after surgery. Intragastric administration of L-citrulline was applied to rats in Cit and CLP+Cit groups before surgery. Serum AST and ALT levels and levels of MDA, SOD, NO, and iNOS in the liver tissues were evaluated. Plasma concentrations of Cit and Arg were assessed using HPLC-MS/MS. Serum concentrations of cytokines and chemokines were calculated by Luminex. Results showed SOD activities of CLP+Cit groups were significantly higher than that of CLP groups, contrasting with the MDA and NO levels which were significantly lower in CLP+Cit groups than in CLP groups. In addition, plasma concentrations of TNF-α, IL-6, and IL-1β were significantly lower in the CLP+Cit 6-hour group than in the CLP 6-hour group. PMID:27195281

  17. L-citrulline for protection of endothelial function from ADMA–induced injury in porcine coronary artery

    PubMed Central

    Xuan, Chao; Lun, Li-Min; Zhao, Jin-Xia; Wang, Hong-Wei; Wang, Jue; Ning, Chun-Ping; Liu, Zhen; Zhang, Bei-Bei; He, Guo-Wei

    2015-01-01

    Endogenous nitric oxide synthase (eNOS) inhibitor asymmetric dimethylarginine (ADMA) is a cardiovascular risk factor. We tested the hypothesis that L-citrulline may ameliorate the endothelial function altered by ADMA in porcine coronary artery (PCA). Myograph study for vasorelaxation, electrochemical measurement for NO, RT-PCR, and Western blot analysis for expression of eNOS, argininosuccinate synthetase (ASS), and p-eNOSser1177 were performed. cGMP was determined by enzyme immunoassay. Superoxide anion (O2.−) production was detected by the lucigenin-enhanced chemiluminescence method. Compare with controls (96.03% ± 6.2%), the maximal relaxation induced by bradykinin was significantly attenuated (61.55% ± 4.8%, p < 0.01), and significantly restored by L-citrulline (82.67 ± 6.4%, p < 0.05) after 24 hours of ADMA exposure. Expression of eNOS, p-eNOSser1177, and ASS in PCA significantly increased after L-citrulline incubation. L-citrulline also markedly restored the NO production, and cGMP level which was reduced by ADMA. The increased O2.− production by ADMA was also inhibited by L-citrulline. L-citrulline restores the endothelial function in preparations treated with ADMA by preservation of NO production and suppression of O2.− generation. Preservation of NO is attributed to the upregulation of eNOS expression along with activation of p-eNOSser1177. L-citrulline improves endothelium-dependent vasodilation through NO/ cGMP pathway. PMID:26046576

  18. L-citrulline for protection of endothelial function from ADMA-induced injury in porcine coronary artery.

    PubMed

    Xuan, Chao; Lun, Li-Min; Zhao, Jin-Xia; Wang, Hong-Wei; Wang, Jue; Ning, Chun-Ping; Liu, Zhen; Zhang, Bei-Bei; He, Guo-Wei

    2015-01-01

    Endogenous nitric oxide synthase (eNOS) inhibitor asymmetric dimethylarginine (ADMA) is a cardiovascular risk factor. We tested the hypothesis that L-citrulline may ameliorate the endothelial function altered by ADMA in porcine coronary artery (PCA). Myograph study for vasorelaxation, electrochemical measurement for NO, RT-PCR, and Western blot analysis for expression of eNOS, argininosuccinate synthetase (ASS), and p-eNOS(ser1177) were performed. cGMP was determined by enzyme immunoassay. Superoxide anion (O2.(-)) production was detected by the lucigenin-enhanced chemiluminescence method. Compare with controls (96.03% ± 6.2%), the maximal relaxation induced by bradykinin was significantly attenuated (61.55% ± 4.8%, p<0.01), and significantly restored by L-citrulline (82.67 ± 6.4%, p<0.05) after 24 hours of ADMA exposure. Expression of eNOS, p-eNOS(ser1177), and ASS in PCA significantly increased after L-citrulline incubation. L-citrulline also markedly restored the NO production, and cGMP level which was reduced by ADMA. The increased O2.(-) production by ADMA was also inhibited by L-citrulline. L-citrulline restores the endothelial function in preparations treated with ADMA by preservation of NO production and suppression of O2.(-) generation. Preservation of NO is attributed to the upregulation of eNOS expression along with activation of p-eNOS(ser1177). L-citrulline improves endothelium-dependent vasodilation through NO/ cGMP pathway. PMID:26046576

  19. Citrulline Protects Streptococcus pyogenes from Acid Stress Using the Arginine Deiminase Pathway and the F1Fo-ATPase

    PubMed Central

    Cusumano, Zachary T.

    2015-01-01

    ABSTRACT A common stress encountered by both pathogenic and environmental bacteria is exposure to a low-pH environment, which can inhibit cell growth and lead to cell death. One major defense mechanism against this stress is the arginine deiminase (ADI) pathway, which catabolizes arginine to generate two ammonia molecules and one molecule of ATP. While this pathway typically relies on the utilization of arginine, citrulline has also been shown to enter into the pathway and contribute to protection against acid stress. In the pathogenic bacterium Streptococcus pyogenes, the utilization of citrulline has been demonstrated to contribute to pathogenesis in a murine model of soft tissue infection, although the mechanism underlying its role in infection is unknown. To gain insight into this question, we analyzed a panel of mutants defective in different steps in the ADI pathway to dissect how arginine and citrulline protect S. pyogenes in a low-pH environment. While protection provided by arginine utilization occurred through the buffering of the extracellular environment, citrulline catabolism protection was pH independent, requiring the generation of ATP via the ADI pathway and a functional F1Fo-ATP synthase. This work demonstrates that arginine and citrulline catabolism protect against acid stress through distinct mechanisms and have unique contributions to virulence during an infection. IMPORTANCE An important aspect of bacterial pathogenesis is the utilization of host-derived nutrients during an infection for growth and virulence. Previously published work from our lab identified a unique role for citrulline catabolism in Streptococcus pyogenes during a soft tissue infection. The present article probes the role of citrulline utilization during this infection and its contribution to protection against acid stress. This work reveals a unique and concerted action between the catabolism of citrulline and the F1Fo-ATPase that function together to provide protection for

  20. Quantitative analysis of 15N labeled positional isomers of glutamine and citrulline via electrospray ionization tandem mass spectrometry of their dansyl derivatives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The enteral metabolism of glutamine and citrulline are intertwined because, while glutamine is one of the main fuel sources for the enterocyte, citrulline is one of its products. It has been shown that the administration of 15N labeled glutamine results in the incorporation of the 15N label into cit...

  1. Acute Citrulline-Malate Supplementation and High-Intensity Cycling Performance.

    PubMed

    Cunniffe, Brian; Papageorgiou, Maria; OʼBrien, Barbara; Davies, Nathan A; Grimble, George K; Cardinale, Marco

    2016-09-01

    Cunniffe, B, Papageorgiou, M, O'Brien, B, Davies, NA, Grimble, GK, and Cardinale, M. Acute citrulline-malate supplementation and high-intensity cycling performance. J Strength Cond Res 30(9): 2638-2647, 2016-Dietary L-citrulline-malate (CM) consumption has been suggested to improve skeletal muscle metabolism and contractile efficiency, which would be expected to predispose exercising individuals to greater fatigue resistance. The purpose of this study was to examine the effects of CM supplementation on acid-base balance and high-intensity exercise performance. In a double-blind, placebo-controlled, crossover study, 10 well-trained males consumed either 12 g of CM (in 400 ml) or lemon sugar-free cordial (placebo [PL]) 60 minutes before completion of 2 exercise trials. Each trial consisted of subjects performing 10 (×15 seconds) maximal cycle sprints (with 30-second rest intervals) followed by 5 minutes recovery before completing a cycle time-to-exhaustion test (TTE) at 100% of individual peak power (PP). Significant increases in plasma concentrations of citrulline (8.8-fold), ornithine (3.9-fold), and glutamine (1.3-fold) were observed 60 minutes after supplementation in the CM trial only (p ≤ 0.05) and none of the subjects experienced gastrointestinal side-effects during testing. Significantly higher exercise heart rates were observed in CM condition (vs. PL) although no between trial differences in performance related variables (TTE: [120 ± 61 seconds CM vs. 113 ± 50 seconds PL]), PP or mean power, ([power fatigue index: 36 ± 16% CM vs. 28 ± 18% PL]), subjective rating of perceived exertion or measures of acid-base balance (pH, lactate, bicarbonate, base-excess) were observed (p > 0.05). This study demonstrated that acute supplementation of 12 g CM does not provide acute ergogenic benefits using the protocol implemented in this study in well-trained males. PMID:26808848

  2. Effects of supplemental citrulline malate ingestion during repeated bouts of lower-body exercise in advanced weightlifters.

    PubMed

    Wax, Benjamin; Kavazis, Andreas N; Weldon, Kevin; Sperlak, Joseph

    2015-03-01

    The purpose of this investigation was to test the efficacy of citrulline malate supplementation on exercise performance, blood lactate, heart rate, and blood pressure during lower-body dynamic resistance exercise. We hypothesized that citrulline malate ingestion before performing submaximal repeated bouts of multiple lower-body resistance exercises would improve performance. Twelve advanced resistance-trained male subjects participated in a randomized, counterbalanced, double-blind study. Subjects were randomly assigned to placebo (PL) or citrulline malate (8 g) groups and then performed repeated bouts of multiple lower-body resistance exercise. Specifically, subjects performed 5 sequential sets (60% 1 repetition maximum) to failure on the leg press, hack squat, and leg extension machines. Blood lactate, heart rate, systolic blood pressure, and diastolic blood pressure were determined before and after exercise. The exercise protocol resulted in sequential significant (p ≤ 0.05) decrease in the number of repetitions in all 3 exercises. However, subjects in the citrulline malate group performed significantly (p ≤ 0.05) higher number of repetitions during all 3 exercises compared with PL group. Blood lactate and heart rate were significantly increased (p ≤ 0.05) after exercise compared with before exercise but were not significantly different between citrulline malate and PL (p > 0.05). No significant (p > 0.05) differences were detected for blood pressure measurements. In conclusion, our results suggest that citrulline malate supplementation may be beneficial in improving exercise performance during lower-body multiple-bout resistance exercise in advanced resistance-trained men. PMID:25226311

  3. Reengineering of a Corynebacterium glutamicum L-arginine and L-citrulline producer.

    PubMed

    Ikeda, Masato; Mitsuhashi, Satoshi; Tanaka, Kenji; Hayashi, Mikiro

    2009-03-01

    Toward the creation of a robust and efficient producer of L-arginine and L-citrulline (arginine/citrulline), we have performed reengineering of a Corynebacterium glutamicum strain by using genetic information of three classical producers. Sequence analysis of their arg operons identified three point mutations (argR123, argG92(up), and argG45) in one producer and one point mutation (argB26 or argB31) in each of the other two producers. Reconstitution of the former three mutations or of each argB mutation on a wild-type genome led to no production. Combined introduction of argB26 or argB31 with argR123 into a wild type gave rise to arginine/citrulline production. When argR123 was replaced by an argR-deleted mutation (Delta argR), the production was further increased. The best mutation set, Delta argR and argB26, was used to screen for the highest productivity in the backgrounds of different wild-type strains of C. glutamicum. This yielded a robust producer, RB, but the production was still one-third of that of the best classical producer. Transcriptome analysis revealed that the arg operon of the classical producer was much more highly upregulated than that of strain RB. Introduction of leuC456, a mutation derived from a classical L-lysine producer and provoking global induction of the amino acid biosynthesis genes, including the arg operon, into strain RB led to increased production but incurred retarded fermentation. On the other hand, replacement of the chromosomal argB by heterologous Escherichia coli argB, natively insensitive to arginine, caused a threefold-increased production without retardation, revealing that the limitation in strain RB was the activity of the argB product. To overcome this, in addition to argB26, the argB31 mutation was introduced into strain RB, which caused higher deregulation of the enzyme and resulted in dramatically increased production, like the strain with E. coli argB. This reconstructed strain displayed an enhanced performance

  4. DR1001 presents ‘altered-self’ peptides derived from joint associated proteins by accepting citrulline in three of its binding pockets

    PubMed Central

    James, Eddie A.; Moustakas, Antonis K.; Bui, John; Papadopoulos, George K.; Bondinas, George; Buckner, Jane H.; Kwok, William W.

    2010-01-01

    Objective HLA-DRB1*1001 (DR1001) is a shared epitope allele associated with rheumatoid arthritis. The objectives of this study were to assess the capacity of DR1001 to accommodate citrulline in its binding pockets and to identify citrullinated T cell epitopes derived from joint associated proteins. Methods The binding of peptide derivatives containing citrulline, arginine, and other amino acid substitutions was measured. A prediction algorithm was then developed to identify arginine containing sequences from joint associated proteins that preferentially bind to DR1001 upon citrullination. Unmodified and citrullinated versions of these sequences were synthesized and utilized to stimulate CD4+ T cells from healthy subjects and rheumatoid arthritis patients. Responses were measured by MHC class II tetramer staining and confirmed by isolating CD4+ T cell clones. Results DR1001 accepted citrulline, but not arginine in three of its anchoring pockets. The prediction algorithm identified sequences that preferentially bound to DR1001 with arginine replaced by citrulline. Three of these sequences elicited CD4+ T cell responses. T cell clones specific for these sequences proliferated only in response to citrullinated peptides. Conclusions Conversion of arginine to citrulline generates ‘altered-self’ peptides that can be bound and presented by DR1001. Responses to these peptides implicate the corresponding proteins (fibrinogen α, fibrinogen β and cartilage intermediate layer protein) as relevant antigens. Preferential responses to citrullinated sequences suggests that altered peptide binding affinity due to this post-translational modification may be an important factor in the initiation or progression of RA. As such, measuring responsiveness to these peptides may be useful for immune monitoring. PMID:20533291

  5. Citrullination as early-stage indicator of cell response to single-walled carbon nanotubes.

    PubMed

    Mohamed, Bashir Mustafa; Movia, Dania; Knyazev, Anton; Langevin, Dominique; Davies, Anthony Mitchell; Prina-Mello, Adriele; Volkov, Yuri

    2013-01-01

    Single-walled carbon nanotubes (SWCNTs) have been widely explored as potential technologies for information systems and medical applications. The impact of SWCNTs on human health is of prime concern, if SWCNTs have a future in the manufacturing industry. This study proposes a novel, inflammation-independent paradigm of toxicity for SWCNTs, identifying the protein citrullination process as early-stage indicator of inflammatory responses of macrophages (THP-1) and of subtle phenotypic damages of lung epithelial (A549) cells following exposure to chemically-treated SWCNTs. Our results showed that, while most of the cellular responses of A549 cells exposed to SWCNTs are different to those of similarly treated THP-1 cells, the protein citrullination process is triggered in a dose- and time-dependent manner in both cell lines, with thresholds comparable between inflammatory (THP-1) and non-inflammatory (A549) cell types. The cellular mechanism proposed herein could have a high impact in predicting the current risk associated with environmental exposure to SWCNTs. PMID:23350031

  6. Citrullination as early-stage indicator of cell response to Single-Walled Carbon Nanotubes

    PubMed Central

    Mohamed, Bashir Mustafa; Movia, Dania; Knyazev, Anton; Langevin, Dominique; Davies, Anthony Mitchell; Prina-Mello, Adriele; Volkov, Yuri

    2013-01-01

    Single-walled carbon nanotubes (SWCNTs) have been widely explored as potential technologies for information systems and medical applications. The impact of SWCNTs on human health is of prime concern, if SWCNTs have a future in the manufacturing industry. This study proposes a novel, inflammation-independent paradigm of toxicity for SWCNTs, identifying the protein citrullination process as early-stage indicator of inflammatory responses of macrophages (THP-1) and of subtle phenotypic damages of lung epithelial (A549) cells following exposure to chemically-treated SWCNTs. Our results showed that, while most of the cellular responses of A549 cells exposed to SWCNTs are different to those of similarly treated THP-1 cells, the protein citrullination process is triggered in a dose- and time-dependent manner in both cell lines, with thresholds comparable between inflammatory (THP-1) and non-inflammatory (A549) cell types. The cellular mechanism proposed herein could have a high impact in predicting the current risk associated with environmental exposure to SWCNTs. PMID:23350031

  7. Citrullination as early-stage indicator of cell response to Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Mohamed, Bashir Mustafa; Movia, Dania; Knyazev, Anton; Langevin, Dominique; Davies, Anthony Mitchell; Prina-Mello, Adriele; Volkov, Yuri

    2013-01-01

    Single-walled carbon nanotubes (SWCNTs) have been widely explored as potential technologies for information systems and medical applications. The impact of SWCNTs on human health is of prime concern, if SWCNTs have a future in the manufacturing industry. This study proposes a novel, inflammation-independent paradigm of toxicity for SWCNTs, identifying the protein citrullination process as early-stage indicator of inflammatory responses of macrophages (THP-1) and of subtle phenotypic damages of lung epithelial (A549) cells following exposure to chemically-treated SWCNTs. Our results showed that, while most of the cellular responses of A549 cells exposed to SWCNTs are different to those of similarly treated THP-1 cells, the protein citrullination process is triggered in a dose- and time-dependent manner in both cell lines, with thresholds comparable between inflammatory (THP-1) and non-inflammatory (A549) cell types. The cellular mechanism proposed herein could have a high impact in predicting the current risk associated with environmental exposure to SWCNTs.

  8. The purified and reconstituted ornithine/citrulline carrier from rat liver mitochondria: electrical nature and coupling of the exchange reaction with H+ translocation.

    PubMed Central

    Indiveri, C; Tonazzi, A; Stipani, I; Palmieri, F

    1997-01-01

    The mechanism and the electrical nature of ornithine/citrulline exchange has been investigated in proteoliposomes reconstituted with the ornithine/citrulline carrier purified from rat liver mitochondria. The stoichiometry of the exchanging substrates was close to 1:1. The exchange was not affected by inducing electrogenic flux of K+ with valinomycin. In contrast, the pH gradient generated by the K+/H+ exchanger nigericin in the presence of an outwardly directed K+ gradient stimulated the ornithineout/citrullinein exchange, but not the ornithine/ornithine homoexchange. Experiments in which either the internal or the external pH was varied, while keeping constant the pH in the other compartment, indicated that maximal exchange rates are found at pH 6 in the compartment containing citrulline and at pH 8 in the compartment containing ornithine. Changes in fluorescence of the pH indicator pyranine, included inside the proteoliposomes, showed that the exchanges ornithineout/citrullinein and citrullineout/ornithinein are accompanied by translocation of H+ in the same direction as citrulline. It is concluded that the mitochondrial ornithine/citrulline carrier catalyses an electroneutral exchange of ornithine+ for citrulline plus an H+. A reasonable model is one in which ornithine binds to a deprotonated carrier and citrulline to a protonated carrier and both substrate-carrier complexes are neutral. The physiological implications of this transport process are discussed. PMID:9359400

  9. Stimulation by D-glucose of the direct conversion of arginine to citrulline in enterocytes isolated from pig jejunum

    SciTech Connect

    Blachier, F.; M'Rabet-Touil, H.; Darcy-Vrillon, B.; Posho, L.; Duee, P.H. )

    1991-06-28

    In enterocytes isolated from pig jejunum, L-arginine is metabolized to L-citrulline either directly or indirectly through the sequence of reactions catalysed by arginase and ornithine transcarbamylase. In the presence of 5 mM D-glucose, the direct conversion of 1mM L-(guanido-14C) arginine to L-citrulline was increased more than 4 times. Isolated enterocytes exhibit a high glycolytic capacity. Furthermore, the decarboxylation of 5mM D-(1-14C) glucose was 3.6 fold higher than the decarboxylation of 5 mM D-(6-14C) glucose which suggests the presence of a pentose phosphate pathway in enterocytes. Since the production of labelled L-citrulline from L-(guanido-14C) arginine in pig enterocyte homogenates was markedly increased in the presence of NADPH, it is proposed that the direct conversion of L-arginine to L-citrulline could be stimulated by the production of NADPH from D-glucose in the pentose phosphate pathway.

  10. Plasma arginine and ornithine are the main citrulline precursors in mice infused with arginine-free diets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dietary arginine is the main dietary precursor for citrulline synthesis, but it is not known if other precursors can compensate for when arginine is absent in the diet. To address this question, the contribution of plasma and dietary precursors were determined, utilizing multitracer protocols in con...

  11. Immune Recognition of Citrullinated Proteoglycan Aggrecan Epitopes in Mice with Proteoglycan-Induced Arthritis and in Patients with Rheumatoid Arthritis

    PubMed Central

    Markovics, Adrienn; Ocskó, Tímea; Katz, Robert S.; Buzás, Edit I.; Glant, Tibor T.

    2016-01-01

    Background Rheumatoid arthritis (RA) is an autoimmune inflammatory disease affecting the joints. Anti-citrullinated protein antibodies (ACPA) are frequently found in RA. Previous studies identified a citrullinated epitope in cartilage proteoglycan (PG) aggrecan that elicited pro-inflammatory cytokine production by RA T cells. We recently reported the presence of ACPA-reactive (citrullinated) PG in RA cartilage. Herein, we sought to identify additional citrullinated epitopes in human PG that are recognized by T cells or antibodies from RA patients. Methods We used mice with PG-induced arthritis (PGIA) as a screening tool to select citrulline (Cit)-containing PG peptides that were more immunogenic than the arginine (R)-containing counterparts. The selected peptide pairs were tested for induction of pro-inflammatory T-cell cytokine production in RA and healthy control peripheral blood mononuclear cell (PBMC) cultures using ELISA and flow cytometry. Anti-Cit and anti-R peptide antibodies were detected by ELISA. Results Splenocytes from mice with PGIA exhibited greater T-cell cytokine secretion in response to the Cit than the R version of PG peptide 49 (P49) and anti-P49 antibodies were found in PGIA serum. PBMC from ACPA+ and ACPA- RA patients, but not from healthy controls, responded to Cit49 with robust cytokine production. High levels of anti-Cit49 antibodies were found in the plasma of a subset of ACPA+ RA patients. Another PG peptide (Cit13) similar to the previously described T-cell epitope induced greater cytokine responses than R13 by control (but not RA) PBMC, however, anti-Cit13 antibodies were rarely detected in human plasma. Conclusions We identified a novel citrullinated PG epitope (Cit49) that is highly immunogenic in mice with PGIA and in RA patients. We also describe T-cell and antibody reactivity with Cit49 in ACPA+ RA. As citrullinated PG might be present in RA articular cartilage, Cit PG epitope-induced T-cell activation or antibody deposition may

  12. Citrulline stimulates muscle protein synthesis in the post-absorptive state in healthy people fed a low-protein diet – A pilot study

    PubMed Central

    Jourdan, Marion; Nair, K. Sreekumaran; Carter, Rickey E.; Schimke, Jill; Ford, G. Charles; Marc, Julie; Aussel, Christian; Cynober, Luc

    2015-01-01

    Background and Aims Amino acid (AA) availability is critical to maintain protein homeostasis and reduced protein intake causes a decline in protein synthesis. Citrulline, an amino acid metabolite, has been reported to stimulate muscle protein synthesis in malnourished rats. Methods To determine whether citrulline stimulates muscle protein synthesis in healthy adults while on a low-protein diet, we studied 8 healthy participants twice in a cross-over study design. Following a 3-days of low-protein intake, either citrulline or a non-essential AA mixture (NEAA) was given orally as small boluses over the course of 8 hours. [ring-13C6] phenylalanine and [15N] tyrosine were administered as tracers to assess protein metabolism. Fractional synthesis rates (FSR) of muscle proteins were measured using phenylalanine enrichment in muscle tissue fluid as the precursor pool. Results FSR of mixed muscle protein was higher during the administration of citrulline than during NEAA (NEAA: 0.049 ± 0.005; citrulline: 0.060 ± 0.006; p=0.03), while muscle mitochondrial protein FSR and whole-body protein turnover were not different between the studies. Citrulline administration increased arginine and ornithine plasma concentrations without any effect on glucose, insulin, C-peptide, and IGF-1 levels. Citrulline administration did not promote mitochondria protein synthesis, transcripts, or citrate synthesis. Conclusions Citrulline ingestion enhances mixed muscle protein synthesis in healthy participants on 3-day low-protein intake. This anabolic action of citrulline appears to be independent of insulin action and may offer potential clinical application in conditions involving low amino acid intake. PMID:24972455

  13. Whole body nitric oxide synthesis in healthy men determined from [15N] arginine-to-[15N]citrulline labeling.

    PubMed Central

    Castillo, L; Beaumier, L; Ajami, A M; Young, V R

    1996-01-01

    The rates of whole body nitric oxide (NO) synthesis, plasma arginine flux, and de novo arginine synthesis and their relationships to urea production, were examined in a total of seven healthy adults receiving an L-amino acid diet for 6 days. NO synthesis was estimated by the rate of conversion of the [15N] guanidino nitrogen of arginine to plasma [15N] ureido citrulline and compared with that based on urinary nitrite (NO2-)/nitrate (NO3-) excretion. Six subjects received on dietary day 7, a 24-hr (12-hr fed/12-hr fasted) primed, constant, intravenous infusion of L-[guanidino-15N2]arginine and [13C]urea. A similar investigation was repeated with three of these subjects, plus an additional subject, in which they received L-[ureido-13C]citrulline, to determine plasma citrulline fluxes. The estimated rates (mean +/- SD) of NO synthesis over a period of 24 hr averaged 0.96 +/- 0.1 mumol .kg-1.hr-1 and 0.95 +/- 0.1 mumol.kg-1.hr-1, for the [15N]citrulline and the nitrite/nitrate methods, respectively. About 15% of the plasma arginine turnover was associated with urea formation and 1.2% with NO formation. De novo arginine synthesis averaged 9.2 +/- 1.4 mumol. kg-1.hr-1, indicating that approximately 11% of the plasma arginine flux originates via conversion of plasma citrulline to arginine. Thus, the fraction of the plasma arginine flux associated with NO and also urea synthesis in healthy humans is small, although the plasma arginine compartment serves as a significant precursor pool (54%) for whole body NO formation. This tracer model should be useful for exploring these metabolic relationships in vivo, under specific pathophysiologic states where the L-arginine-NO pathway might be altered. Images Fig. 4 PMID:8876157

  14. Dietary Arginine Requirements for Growth Are Dependent on the Rate of Citrulline Production in Mice123

    PubMed Central

    Marini, Juan C; Agarwal, Umang; Didelija, Inka C

    2015-01-01

    Background: In many species, including humans, arginine is considered a semiessential amino acid because under certain conditions endogenous synthesis cannot meet its demand. The requirements of arginine for growth in mice are ill defined and seem to vary depending on the genetic background of the mice. Objective: The objective of this study was to determine the metabolic and molecular basis for the requirement of arginine in 2 mouse strains. Methods: Institute of Cancer Research (ICR) and C57BL/6 (BL6) male mice were fed arginine-free or arginine-sufficient diets (Expt. 1) or 1 of 7 diets with increasing arginine concentration (from 0- to 8-g/kg diet, Expt. 2) between day 24 and 42 of life to determine the arginine requirements for growth. Citrulline production and “de novo” arginine synthesis were measured with use of stable isotopes, and arginine requirements were determined by breakpoint analysis and enzyme expression by reverse transcriptase-polymerase chain reaction. Results: In Expt. 1, ICR mice grew at the same rate regardless of the arginine concentration of the diet (mean ± SE: 0.66 ± 0.04 g/d, P = 0.80), but BL6 mice had a reduced growth rate when fed the arginine-free diet (0.25 ± 0.02 g/d, P < 0.001) compared to the 8-g arginine/kg diet (0.46 ± 0.03 g/d). ICR mice showed at least a 2-fold greater expression (P < 0.001) of ornithine transcarbamylase (OTC) than BL6 mice, which translated into a greater rate of citrulline (25%) and arginine synthesis (49%, P < 0.002). In Expt. 2, breakpoint analysis showed that the requirement for growth of BL6 mice was met with 2.32 ± 0.39 g arginine/kg diet; for ICR mice, however, no breakpoint was found. Conclusion: Our data indicate that a reduced expression of OTC in BL6 mice translates into a reduced production of citrulline and arginine compared with ICR mice, which results in a dietary arginine requirement for growth in BL6 mice, but not in ICR mice. PMID:25855119

  15. Investigations on the growth and characterization of L-citrulline oxalate monohydrate single crystal

    NASA Astrophysics Data System (ADS)

    Sreevalsa, V. G.; Jayalekshmi, S.

    2011-06-01

    New single crystals of L-citrulline oxalate (LCO) monohydrate are grown from aqueous solution by slow evaporation technique. Structure and morphology of the grown crystals are identified by single crystal XRD. The compound crystallizes in the orthorhombic structure with space group P2 12 12 1, having cell parameters, a=5.208(5) Å, b=9.829(5) Å and c=23.879(5) Å. Powder X-ray diffraction data is used for the assignment of the hkl values. The chemical composition of the synthesized crystals is verified by CHN analysis. Functional groups present in the sample are identified by Fourier transform infra red (FT-IR) and FT-Raman spectral analysis. The second harmonic signal generated by the crystal using pulsed Nd: YAG Laser is confirmed by the emission of green radiation, showing that the crystal is a potential candidate for nonlinear optical studies.

  16. Chronic l-citrulline supplementation improves cardiac sympathovagal balance in obese postmenopausal women: A preliminary report.

    PubMed

    Wong, Alexei; Chernykh, Oksana; Figueroa, Arturo

    2016-07-01

    The present study evaluated the impact of chronic l-citrulline (L-cit) supplementation on resting heart rate variability (HRV) and blood pressure (BP) in obese postmenopausal women. Participants were randomly assign to either an L-cit group (n=12) or a control group (n=11). HRV and BP were measured before and after 8weeks. There were significant decreases (P<0.05) in nLF (sympathetic activity), LnLF/LnHF (sympathovagal balance), and BP as well as a significant increase (P<0.05) in nHF (vagal tone) following L-cit compared with no changes after control. Our findings indicate that L-cit supplementation improves sympathovagal balance in obese postmenopausal women. PMID:27356482

  17. Anti-Citrullinated Peptide Antibody (ACPA) Assays and their Role in the Diagnosis of Rheumatoid Arthritis

    PubMed Central

    Aggarwal, Rohit; Liao, Katherine; Nair, Raj; Ringold, Sarah; Costenbader, Karen H.

    2010-01-01

    Increasingly, assays for the detection of anti-citrullinated peptide antibodies (ACPA) are used in RA diagnosis. This review summarizes the biologic basis and development of ACPA assays, available ACPA assays and their performance characteristics, and diagnostic properties of ACPA alone and compared to rheumatoid factor (RF) in early RA. We also review correlations, precision, costs and cost-effectiveness, availability, stability and reproducibility of the available assays. Taken together, data indicate that ACPA has a higher specificity than RF for early RA, good predictive validity, high sensitivity, apparent cost-effectiveness and good stability and reproducibility. Given its superior performance characteristics and increasing availability, ACPA is emerging as the most useful single assay for the diagnosis of RA. PMID:19877103

  18. DL-7-azatryptophan and citrulline metabolism in the cyanobacterium Anabaena sp. strain 1F

    SciTech Connect

    Chen, C.H.; Van Baalen, C.; Tabita, F.R.

    1987-03-01

    An alternative route for the primary assimilation of ammonia proceeds via glutamine synthetase-carbamyl phosphate synthetase and its inherent glutaminase activity in Anabaena sp. strain 1F, a marine filamentous, heterocystous cyanobacterium. Evidence for the presence of this possible alternative route to glutamate was provided by the use of amino acid analogs as specific enzyme inhibitors, enzymological studies, and radioistopic labeling experiments. The amino acid pool patterns of continuous cultures of Anabaena sp. strain 1F were markedly influenced by the nitrogen source. A relatively high concentration of glutamate was maintained in the amino acid pools of all cultures irrespective of the nitrogen source, reflecting the central role of glutamate in nitrogen metabolism. The addition of 1.0 microM azaserine increased the intracellular pools of glutamate and glutamine. All attempts to detect any enzymatic activity for glutamate synthase by measuring the formation of L-(/sup 14/C)glutamate from 2-keto-(1-/sup 14/C)glutarate and glutamine failed. The addition of 10 microM DL-7-azatryptophan caused a transient accumulation of intracellular citrulline and alanine which was not affected by the presence of chloramphenicol. The in vitro activity of carbamyl phosphate synthetase and glutaminase increased severalfold in the presence of azatryptophan. Results from radioisotopic labeling experiments with (/sup 14/C)bicarbonate and L-(1-/sup 14/C)ornithine also indicated that citrulline was formed via carbamyl phosphate synthetase and ornithine transcarbamylase. In addition to its effects on nitrogen metabolism, azatryptophan also affected carbon metabolism by inhibiting photosynthetic carbon assimilation and photosynthetic oxygen evolution.

  19. Contribution of Citrulline Ureidase to Francisella tularensis Strain Schu S4 Pathogenesis▿

    PubMed Central

    Mahawar, Manish; Kirimanjeswara, Girish S.; Metzger, Dennis W.; Bakshi, Chandra Shekhar

    2009-01-01

    The citrulline ureidase (CTU) activity has been shown to be associated with highly virulent Francisella tularensis strains, including Schu S4, while it is absent in avirulent or less virulent strains. A definitive role of the ctu gene in virulence and pathogenesis of F. tularensis Schu S4 has not been assessed; thus, an understanding of the significance of this phenotype is long overdue. CTU is a carbon-nitrogen hydrolase encoded by the citrulline ureidase (ctu) gene (FTT0435) on the F. tularensis Schu S4 genome. In the present study, we evaluated the contribution of the ctu gene in the virulence of category A agent F. tularensis Schu S4 by generating a nonpolar deletion mutant, the Δctu mutant. The deletion of the ctu gene resulted in loss of CTU activity, which was restored by transcomplementing the ctu gene. The Δctu mutant did not exhibit any growth defect under acellular growth conditions; however, it was impaired for intramacrophage growth in resting as well as gamma interferon-stimulated macrophages. The Δctu mutant was further tested for its virulence attributes in a mouse model of respiratory tularemia. Mice infected intranasally with the Δctu mutant showed significantly reduced bacterial burden in the lungs, liver, and spleen compared to wild-type (WT) Schu S4-infected mice. The reduced bacterial burden in mice infected with the Δctu mutant was also associated with significantly lower histopathological scores in the lungs. Mice infected with the Δctu mutant succumbed to infection, but they survived longer and showed significantly extended median time to death compared to that shown by WT Schu S4-infected mice. To conclude, this study demonstrates that ctu contributes to intracellular survival, in vivo growth, and pathogenesis. However, ctu is not an absolute requirement for the virulence of F. tularensis Schu S4 in mice. PMID:19502406

  20. Effect of Teduglutide, a Glucagon-like Peptide 2 Analog, on Citrulline Levels in Patients With Short Bowel Syndrome in Two Phase III Randomized Trials

    PubMed Central

    Seidner, Douglas L; Joly, Francisca; Youssef, Nader N

    2015-01-01

    Objectives: In clinical trials, treatment with the glucagon-like peptide 2 analog teduglutide was associated with improved fluid and nutrient absorption and increased intestinal villus height and crypt depth in patients with short bowel syndrome (SBS). Plasma citrulline, an amino acid produced by enterocytes, is considered a measure of enterocyte mass. This analysis assessed changes in plasma citrulline levels in patients with SBS in 2 phase III clinical studies of teduglutide. Methods: Both teduglutide studies (0.05 or 0.10 mg/kg/day in CL0600-004 and 0.05 mg/kg/day in CL0600-020) were phase III, 24-week, double-blind, and placebo controlled. Plasma citrulline levels were analyzed and validated by liquid chromatography coupled to tandem mass spectrometry. Results: In both the CL0600-004 and CL0600-020 studies, change in mean plasma citrulline concentrations at Week 24 vs. baseline was significantly greater with teduglutide compared with placebo (10.9 (0.05-mg/kg/day dose) and 15.7 (0.10-mg/kg/day dose) vs. 2.0 μmol/L and 20.6 vs. 0.7 μmol/L, respectively, for each study (P≤0.0001 for each comparison with placebo)). Teduglutide treatment was associated with reductions from baseline in PS (parenteral support) volume requirements; however, a significant correlation between PS reduction and increase in plasma citrulline at Week 24 was observed in only one out of the three teduglutide treatment groups. Conclusions: In 2 phase III studies, patients receiving teduglutide had significant increases in plasma citrulline at Week 24 compared with patients receiving placebo. Increases in plasma citrulline concentrations likely reflect enterocyte mass expansion, but no clear correlation was detected between change in plasma citrulline and change in weekly PS volume. PMID:26111125

  1. Effects of acute ammonia toxicity on nitric oxide (NO), citrulline-NO cycle enzymes, arginase and related metabolites in different regions of rat brain.

    PubMed

    Swamy, M; Zakaria, Adlin Zafrulan; Govindasamy, Chandran; Sirajudeen, K N S; Nadiger, H A

    2005-10-01

    Nitric oxide (NO) is involved in many pathophysiological processes in the brain. NO is synthesized from arginine by nitric oxide synthase (NOS) enzymes. Citrulline formed as a by-product of the NOS reaction, can be recycled to arginine by successive actions of argininosuccinate synthetase (ASS) and argininosuccinate lyase (ASL) via the citrulline-NO cycle. Hyperammonemia is known to cause poorly understood perturbations of the citrulline-NO cycle. To understand the role of citrulline-NO cycle in hyperammonemia, NOS, ASS, ASL and arginase activities, as well as nitrate/nitrite (NOx), arginine, ornithine, citrulline, glutamine, glutamate and GABA were estimated in cerebral cortex (CC), cerebellum (CB) and brain stem (BS) of rats subjected to acute ammonia toxicity. NOx concentration and NOS activity were found to increase in all the regions of brain in acute ammonia toxicity. The activities of ASS and ASL showed an increasing trend whereas the arginase was not changed. The results of this study clearly demonstrated the increased formation of NO, suggesting the involvement of NO in the pathophysiology of acute ammonia toxicity. The increased activities of ASS and ASL suggest the increased and effective recycling of citrulline to arginine in acute ammonia toxicity, making NO production more effective and contributing to its toxic effects. PMID:16009439

  2. Studies on L-citrulline doped potassium dihydrogen phosphate- A non linear crystal with significant nonlinear properties

    NASA Astrophysics Data System (ADS)

    Sreevalsa, V. G.; Jayalekshmi, S.

    2014-01-01

    Potassium Dihydrogen Phosphate (KDP) single crystal is considered as one of the best representative of nonlinear optical crystals. Recently, amino acids having excellent nonlinear optical characteristics are being investigated as prospective dopants to improve the non linear optical characteristics of KDP. The present work is an attempt in this direction and L citrulline, one of the non essential amino acids showing good non linear optical characteristics is used as the dopant for KDP. Good quality crystals of L-citrulline doped KDP crystals were grown by slow evaporation technique. From the powder X-ray diffraction studies of doped KDP crystal, the structure of the doped crystals was determined by direct method and refined by Pawley method employing Topaz version program using the single crystal X-ray data for pure KDP. The lattice parameters for L citrulline doped KDP are a=7.467A0, b=7.467 A0, c=6.977 A0. The crystal falls into the tetragonal crystal system with space group I42 d. The presence of carbon and oxygen, which are primary components of amino acids, in the EDAX spectrum confirms the effectiveness of doping. The absorption spectra of the doped samples show that the crystals are transparent in the entire visible region. The second harmonic generation efficiency of the doped samples was determined by Kurtz powder technique using the Q-switched Nd:YAG laser beam and is found to be 2.2 times that of KDP. The nonlinear optical properties can be well studied by the open aperture Z scan technique. The open aperture curve exhibits a normalized transmittance valley. The nonlinear absorption coefficient β is obtained by theoretical fitting for two photon absorption. It is inferred that doping KDP with L citrulline has enhanced the nonlinearity considerably. This obviously suggests the potentiality of the crystal as an optical power limiter and also for various optical device applications.

  3. Studies on L-citrulline doped potassium dihydrogen phosphate- A non linear crystal with significant nonlinear properties

    SciTech Connect

    Sreevalsa, V. G. E-mail: jayalekshmi@cusat.ac.in; Jayalekshmi, S. E-mail: jayalekshmi@cusat.ac.in

    2014-01-28

    Potassium Dihydrogen Phosphate (KDP) single crystal is considered as one of the best representative of nonlinear optical crystals. Recently, amino acids having excellent nonlinear optical characteristics are being investigated as prospective dopants to improve the non linear optical characteristics of KDP. The present work is an attempt in this direction and L citrulline, one of the non essential amino acids showing good non linear optical characteristics is used as the dopant for KDP. Good quality crystals of L-citrulline doped KDP crystals were grown by slow evaporation technique. From the powder X-ray diffraction studies of doped KDP crystal, the structure of the doped crystals was determined by direct method and refined by Pawley method employing Topaz version program using the single crystal X-ray data for pure KDP. The lattice parameters for L citrulline doped KDP are a=7.467A{sup 0}, b=7.467 A{sup 0}, c=6.977 A{sup 0}. The crystal falls into the tetragonal crystal system with space group I42 d. The presence of carbon and oxygen, which are primary components of amino acids, in the EDAX spectrum confirms the effectiveness of doping. The absorption spectra of the doped samples show that the crystals are transparent in the entire visible region. The second harmonic generation efficiency of the doped samples was determined by Kurtz powder technique using the Q-switched Nd:YAG laser beam and is found to be 2.2 times that of KDP. The nonlinear optical properties can be well studied by the open aperture Z scan technique. The open aperture curve exhibits a normalized transmittance valley. The nonlinear absorption coefficient β is obtained by theoretical fitting for two photon absorption. It is inferred that doping KDP with L citrulline has enhanced the nonlinearity considerably. This obviously suggests the potentiality of the crystal as an optical power limiter and also for various optical device applications.

  4. Modular pathway engineering of Corynebacterium glutamicum for production of the glutamate-derived compounds ornithine, proline, putrescine, citrulline, and arginine.

    PubMed

    Jensen, Jaide V K; Eberhardt, Dorit; Wendisch, Volker F

    2015-11-20

    The glutamate-derived bioproducts ornithine, citrulline, proline, putrescine, and arginine have applications in the food and feed, cosmetic, pharmaceutical, and chemical industries. Corynebacterium glutamicum is not only an excellent producer of glutamate but also of glutamate-derived products. Here, engineering targets beneficial for ornithine production were identified and the advantage of rationally constructing a platform strain for the production of the amino acids citrulline, proline, and arginine, and the diamine putrescine was demonstrated. Feedback alleviation of N-acetylglutamate kinase, tuning of the promoter of glutamate dehydrogenase gene gdh, lowering expression of phosphoglucoisomerase gene pgi, along with the introduction of a second copy of the arginine biosynthesis operon argCJB(A49V,M54V)D into the chromosome resulted in a C. glutamicum strain producing ornithine with a yield of 0.52 g ornithine per g glucose, an increase of 71% as compared to the parental ΔargFRG strain. Strains capable of producing 0.41 g citrulline per g glucose, 0.29 g proline per g glucose, 0.30 g arginine per g glucose, and 0.17 g putrescine per g glucose were derived from the ornithine-producing platform strain by plasmid-based overexpression of appropriate pathway modules with one to three genes. PMID:26393954

  5. Comparison of Two Assays to Determine Anti-Citrullinated Peptide Antibodies in Rheumatoid Arthritis in relation to Other Chronic Inflammatory Rheumatic Diseases: Assaying Anti-Modified Citrullinated Vimentin Antibodies Adds Value to Second-Generation Anti-Citrullinated Cyclic Peptides Testing

    PubMed Central

    Díaz-Toscano, Miriam Lizette; Olivas-Flores, Eva Maria; Zavaleta-Muñiz, Soraya Amali; Gamez-Nava, Jorge Ivan; Cardona-Muñoz, Ernesto German; Ponce-Guarneros, Manuel; Castro-Contreras, Uriel; Nava, Arnulfo; Salazar-Paramo, Mario; Celis, Alfredo; Fajardo-Robledo, Nicte Selene; Corona-Sanchez, Esther Guadalupe; Gonzalez-Lopez, Laura

    2014-01-01

    Determination of anti-citrullinated peptide antibodies (ACPA) plays a relevant role in the diagnosis of rheumatoid arthritis (RA). To date, it is still unclear if the use of several tests for these autoantibodies in the same patient offers additional value as compared to performing only one test. Therefore, we evaluated the performance of using two assays for ACPA: second-generation anti-citrullinated cyclic peptides antibodies (anti-CCP2) and anti-mutated citrullinated vimentin (anti-MCV) antibodies for the diagnosis of RA. We compared three groups: RA (n = 142), chronic inflammatory disease (CIRD, n = 86), and clinically healthy subjects (CHS, n = 56) to evaluate sensitivity, specificity, predictive values, and likelihood ratios (LR) of these two assays for the presence of RA. A lower frequency of positivity for anti-CCP2 was found in RA (66.2%) as compared with anti-MCV (81.0%). When comparing RA versus other CIRD, sensitivity increased when both assays were performed. This strategy of testing both assays had high specificity and LR+. We conclude that adding the assay of anti-MCV antibodies to the determination of anti-CCP2 increases the sensitivity for detecting seropositive RA. Therefore, we propose the use of both assays in the initial screening of RA in longitudinal studies, including early onset of undifferentiated arthritis. PMID:25025037

  6. Comparison of two assays to determine anti-citrullinated peptide antibodies in rheumatoid arthritis in relation to other chronic inflammatory rheumatic diseases: assaying anti-modified citrullinated vimentin antibodies adds value to second-generation anti-citrullinated cyclic peptides testing.

    PubMed

    Díaz-Toscano, Miriam Lizette; Olivas-Flores, Eva Maria; Zavaleta-Muñiz, Soraya Amali; Gamez-Nava, Jorge Ivan; Cardona-Muñoz, Ernesto German; Ponce-Guarneros, Manuel; Castro-Contreras, Uriel; Nava, Arnulfo; Salazar-Paramo, Mario; Celis, Alfredo; Fajardo-Robledo, Nicte Selene; Corona-Sanchez, Esther Guadalupe; Gonzalez-Lopez, Laura

    2014-01-01

    Determination of anti-citrullinated peptide antibodies (ACPA) plays a relevant role in the diagnosis of rheumatoid arthritis (RA). To date, it is still unclear if the use of several tests for these autoantibodies in the same patient offers additional value as compared to performing only one test. Therefore, we evaluated the performance of using two assays for ACPA: second-generation anti-citrullinated cyclic peptides antibodies (anti-CCP2) and anti-mutated citrullinated vimentin (anti-MCV) antibodies for the diagnosis of RA. We compared three groups: RA (n = 142), chronic inflammatory disease (CIRD, n = 86), and clinically healthy subjects (CHS, n = 56) to evaluate sensitivity, specificity, predictive values, and likelihood ratios (LR) of these two assays for the presence of RA. A lower frequency of positivity for anti-CCP2 was found in RA (66.2%) as compared with anti-MCV (81.0%). When comparing RA versus other CIRD, sensitivity increased when both assays were performed. This strategy of testing both assays had high specificity and LR+. We conclude that adding the assay of anti-MCV antibodies to the determination of anti-CCP2 increases the sensitivity for detecting seropositive RA. Therefore, we propose the use of both assays in the initial screening of RA in longitudinal studies, including early onset of undifferentiated arthritis. PMID:25025037

  7. Structure and mechanism of a bacterial host-protein citrullinating virulence factor, Porphyromonas gingivalis peptidylarginine deiminase

    PubMed Central

    Goulas, Theodoros; Mizgalska, Danuta; Garcia-Ferrer, Irene; Kantyka, Tomasz; Guevara, Tibisay; Szmigielski, Borys; Sroka, Aneta; Millán, Claudia; Usón, Isabel; Veillard, Florian; Potempa, Barbara; Mydel, Piotr; Solà, Maria; Potempa, Jan; Gomis-Rüth, F. Xavier

    2015-01-01

    Citrullination is a post-translational modification of higher organisms that deiminates arginines in proteins and peptides. It occurs in physiological processes but also pathologies such as multiple sclerosis, fibrosis, Alzheimer’s disease and rheumatoid arthritis (RA). The reaction is catalyzed by peptidylarginine deiminases (PADs), which are found in vertebrates but not in lower organisms. RA has been epidemiologically associated with periodontal disease, whose main infective agent is Porphyromonas gingivalis. Uniquely among microbes, P. gingivalis secretes a PAD, termed PPAD (Porphyromonas peptidylarginine deiminase), which is genetically unrelated to eukaryotic PADs. Here, we studied function of PPAD and its substrate-free, substrate-complex, and substrate-mimic-complex structures. It comprises a flat cylindrical catalytic domain with five-fold α/β-propeller architecture and a C-terminal immunoglobulin-like domain. The PPAD active site is a funnel located on one of the cylinder bases. It accommodates arginines from peptide substrates after major rearrangement of a “Michaelis loop” that closes the cleft. The guanidinium and carboxylate groups of substrates are tightly bound, which explains activity of PPAD against arginines at C-termini but not within peptides. Catalysis is based on a cysteine-histidine-asparagine triad, which is shared with human PAD1-PAD4 and other guanidino-group modifying enzymes. We provide a working mechanism hypothesis based on 18 structure-derived point mutants. PMID:26132828

  8. Presence of antibodies against cyclic citrullinated peptides in patients with 'rhupus': a cross-sectional study

    PubMed Central

    Amezcua-Guerra, Luis M; Springall, Rashidi; Marquez-Velasco, Ricardo; Gómez-García, Lorena; Vargas, Angélica; Bojalil, Rafael

    2006-01-01

    'Rhupus' is a rare condition sharing features of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). If rhupus is a distinctive entity, an overlap between RA and SLE or a subset of SLE is currently debated. This study was performed to explore the prevalence of antibodies against cyclic citrullinated peptides (anti-CCP antibodies) in rhupus. Patients meeting American College of Rheumatology criteria for RA, SLE, or both were included. Clinical and radiographic features were recorded and sera were searched for anti-CCP antibodies, rheumatoid factor, antinuclear antibodies, anti-extractable nuclear antigens, and antibodies against double-stranded DNA (anti-dsDNA antibodies). Seven patients for each group were included. Clinical and serological features for RA or SLE were similar between rhupus and RA patients, and between rhupus and SLE patients, respectively. Values for anti-CCP antibodies obtained were significantly (p < 0.05) higher in RA (6/7) and rhupus (4/7) than in SLE patients (0/7) and healthy subjects (0/7). Our data support the possibility that rhupus is an overlap between RA and SLE, because highly specific autoantibodies for RA (anti-CCP) and for SLE (anti-dsDNA and anti-Sm) are detected in coexistence. PMID:16934155

  9. Anti-Citrullinated Protein Antibodies Induce Macrophage Subset Disequilibrium in RA Patients.

    PubMed

    Zhu, Wei; Li, Xiu; Fang, Shaohong; Zhang, Xiaoli; Wang, Ying; Zhang, Tongshuai; Li, Zhaoying; Xu, Yanwen; Qu, Siying; Liu, Chuanliang; Gao, Fei; Pan, Haile; Wang, Guangyou; Li, Hulun; Sun, Bo

    2015-12-01

    We used samples from rheumatoid arthritis (RA) patients to examine whether Anti-citrullinated protein antibodies (ACPAs) alter macrophage subset distribution and promote RA development. Macrophage subset distributions and interferon regulatory factor 4 (IRF4) and IRF5 expressions were analyzed. ACPAs were purified by affinity column. After RA and osteoarthritis (OA) patients' macrophages were cocultured with ACPAs, macrophage subsets and IRF4 and IRF5 expressions were measured. Small interfering RNAs (siRNAs) were transfected into ACPA-activated cells to suppress IRF4 or IRF5. Fluorescence-activated cell sorting (FACS), Western blot, and immunohistochemistry were performed. Macrophage subset disequilibrium occurred in RA patient synovial fluids. IRF4 and IRF5 were all expressed in the synovial fluid and synovium. ACPAs (40 IU/ml) could induce macrophages to polarize to M1 subsets, and the percentage of increased M1/M2 ratio of RA patients was higher than that of the OA patients. ACPAs also induce IRF4 and IRF5 protein expressions. IRF5 siRNA transfection impaired ACPA activity significantly. We demonstrated that macrophage subset disequilibrium occurred in RA patients. ACPAs induced IRF5 activity and led to M1 macrophage polarization. PMID:26063186

  10. Asymmetric Dimethylarginine Is a Well Established Mediating Risk Factor for Cardiovascular Morbidity and Mortality-Should Patients with Elevated Levels Be Supplemented with Citrulline?

    PubMed

    McCarty, Mark F

    2016-01-01

    The arginine metabolite asymmetric dimethylarginine (ADMA) is a competitive inhibitor and uncoupler of endothelial nitric oxide synthase (eNOS), an enzyme that acts in multifarious ways to promote cardiovascular health. This phenomenon likely explains, at least in part, why elevated ADMA has been established as an independent risk factor for cardiovascular events, ventricular hypertrophy, and cardiovascular mortality. Fortunately, the suppressive impact of ADMA on eNOS activity can be offset by increasing intracellular arginine levels with supplemental citrulline. Although the long-term impact of supplemental citrulline on cardiovascular health in patients with elevated ADMA has not yet been studied, shorter-term clinical studies of citrulline administration demonstrate effects suggestive of increased NO synthesis, such as reductions in blood pressure and arterial stiffness, improved endothelium-dependent vasodilation, increased erection hardness, and increased ejection fractions in patients with heart failure. Supplemental citrulline could be a practical option for primary or secondary prevention of cardiovascular events and mortality, as it is inexpensive, has a mild flavor, and is well tolerated in doses (3-6 g daily) that can influence eNOS activity. Large and long-term clinical trials, targeting patients at high risk for cardiovascular events in whom ADMA is elevated, are needed to evaluate citrulline's potential for aiding cardiovascular health. PMID:27417628

  11. Autoantibodies to citrullinated proteins induce joint pain independent of inflammation via a chemokine-dependent mechanism

    PubMed Central

    Wigerblad, Gustaf; Bas, Duygu B; Fernades-Cerqueira, Cátia; Krishnamurthy, Akilan; Rogoz, Katarzyna; Kato, Jungo; Sandor, Katalin; Su, Jie; Jimenez–Andrade, Juan Miguel; Finn, Anja; Bersellini Farinotti, Alex; Amara, Khaled; Lundberg, Karin; Holmdahl, Rikard; Jakobsson, Per-Johan; Malmström, Vivianne; Catrina, Anca I; Klareskog, Lars; Svensson, Camilla I

    2016-01-01

    Objective An interesting and so far unexplained feature of chronic pain in autoimmune disease is the frequent disconnect between pain and inflammation. This is illustrated well in rheumatoid arthritis (RA) where pain in joints (arthralgia) may precede joint inflammation and persist even after successful anti-inflammatory treatment. In the present study, we have addressed the possibility that autoantibodies against citrullinated proteins (ACPA), present in RA, may be directly responsible for the induction of pain, independent of inflammation. Methods Antibodies purified from human patients with RA, healthy donors and murinised monoclonal ACPA were injected into mice. Pain-like behaviour was monitored for up to 28 days, and tissues were analysed for signs of pathology. Mouse osteoclasts were cultured and stimulated with antibodies, and supernatants analysed for release of factors. Mice were treated with CXCR1/2 (interleukin (IL) 8 receptor) antagonist reparixin. Results Mice injected with either human or murinised ACPA developed long-lasting pronounced pain-like behaviour in the absence of inflammation, while non-ACPA IgG from patients with RA or control monoclonal IgG were without pronociceptive effect. This effect was coupled to ACPA-mediated activation of osteoclasts and release of the nociceptive chemokine CXCL1 (analogue to human IL-8). ACPA-induced pain-like behaviour was reversed with reparixin. Conclusions The data suggest that CXCL1/IL-8, released from osteoclasts in an autoantibody-dependent manner, produces pain by activating sensory neurons. The identification of this new pain pathway may open new avenues for pain treatment in RA and also in other painful diseases associated with autoantibody production and/or osteoclast activation. PMID:26613766

  12. Anti-citrullinated peptide antibodies and their value for predicting responses to biologic agents: a review.

    PubMed

    Martin-Mola, Emilio; Balsa, Alejandro; García-Vicuna, Rosario; Gómez-Reino, Juan; González-Gay, Miguel Angel; Sanmartí, Raimon; Loza, Estíbaliz

    2016-08-01

    Anti-citrullinated peptide antibodies (ACPAs) play an important pathogenic role both at the onset and during the disease course. These antibodies precede the clinical appearance of rheumatoid arthritis (RA) and are associated with a less favorable prognosis, both clinically and radiologically. The objective of this work was to conduct a comprehensive review of studies published through September 2015 of ACPAs' role as a predictor of the therapeutic response to the biological agents in RA patients. The review also includes summary of the biology and detection of ACPAs as well as ACPAs in relation to joint disease and CV disease and the possible role of seroconversion. The reviews of studies examining TNF inhibitors and tocilizumab yielded negative results. In the case of rituximab, the data indicated a greater probability of clinical benefit in ACPA(+) patients versus ACPA(-) patients, as has been previously described for rheumatoid factor. Nonetheless, the effect is discreet and heterogeneous. Another drug that may have greater effectiveness in ACPA(+) patients is abatacept. Some studies have suggested that the drug is more efficient in ACPA(+) patients and that those patients show greater drug retention. In a subanalysis of the AMPLE trial, patients with very high ACPA titers who were treated with abatacept had a statistically significant response compared to patients with lower titers. In summary, the available studies suggest that the presence of or high titers of ACPA may predict a better response to rituximab and/or abatacept. Evidence regarding TNFi and tocilizumab is lacking. However, there is a lack of studies with appropriate designs to demonstrate that some drugs are superior to others for ACPA(+) patients. PMID:27271502

  13. Serum citrulline as a biomarker of gastrointestinal function during hematopoietic cell transplantation (HCT) in children

    PubMed Central

    Gosselin, Kerri B.; Feldman, Henry A.; Sonis, Andrew L.; Bechard, Lori J.; Kellogg, Mark D.; Gura, Kathleen; Venick, Robert; Gordon, Catherine M.; Guinan, Eva C.; Duggan, Christopher

    2014-01-01

    Objective We sought to determine if serum citrulline (CIT), an amino acid produced by small bowel enterocytes, was associated with clinical and biochemical markers of gastrointestinal function in children undergoing hematopoietic cell transplantation (HCT). Methods We conducted a multi-center, prospective cohort study of 26 children to define time-related changes in serum CIT over the course of HCT. Markers of gastrointestinal function including oral energy intake, emesis, stool volume, presence of graft-versus-host disease (GVHD), oral mucositis severity, and cytokine and neurohormone levels were measured. Weekly serum CIT concentrations were obtained from 10 days prior until 30 days after HCT. Results Mean baseline CIT concentration was 22.7 µmol/L (95% CI 17.7 – 27.6) on day −10, which decreased to a nadir of 7.5 µmol/L (95% CI 3.1 – 18.0, p = 0.017) on day +8 following HCT before returning to baseline by day 30. After adjustment for IL-6 level (1.0% lower CIT per 10% increase in IL-6, p=0.004), presence of acute graft-versus-host disease (GVHD), (27% lower CIT, p=0.025) and oral energy intake (2.1% lower CIT per 10% decrease in energy intake, p=0.018), the nadir shifted to day +10, when mean CIT concentration was lower in patients with severe oral mucositis (6.7 µmol/L, 95% CI 3.4–13.1) than in those without severe mucositis (11.9 µmol/L, 95% CI 5.8–24.4, p=0.003). Change in CIT was not correlated with stool volume, C-reactive protein, TNF-alpha, leptin, or ghrelin. Conclusion In children undergoing HCT, serum CIT correlates with measures of gastrointestinal function (oral mucositis severity, dietary intake, acute GVHD) and may reflect mucosal injury to the gastrointestinal tract. PMID:24614125

  14. Reduced TCR‐dependent activation through citrullination of a T‐cell epitope enhances Th17 development by disruption of the STAT3/5 balance

    PubMed Central

    Tibbitt, Christopher; Falconer, Jane; Stoop, Jeroen; van Eden, Willem; Robinson, John H.

    2016-01-01

    Citrullination is a post‐translational modification of arginine that commonly occurs in inflammatory tissues. Because T‐cell receptor (TCR) signal quantity and quality can regulate T‐cell differentiation, citrullination within a T‐cell epitope has potential implications for T‐cell effector function. Here, we investigated how citrullination of an immunedominant T‐cell epitope affected Th17 development. Murine naïve CD4+ T cells with a transgenic TCR recognising p89‐103 of the G1 domain of aggrecan (agg) were co‐cultured with syngeneic bone marrow‐derived dendritic cells (BMDC) presenting the native or citrullinated peptides. In the presence of pro‐Th17 cytokines, the peptide citrullinated on residue 93 (R93Cit) significantly enhanced Th17 development whilst impairing the Th2 response, compared to the native peptide. T cells responding to R93Cit produced less IL‐2, expressed lower levels of the IL‐2 receptor subunit CD25, and showed reduced STAT5 phosphorylation, whilst STAT3 activation was unaltered. IL‐2 blockade in native p89‐103‐primed T cells enhanced the phosphorylated STAT3/STAT5 ratio, and concomitantly enhanced Th17 development. Our data illustrate how a post‐translational modification of a TCR contact point may promote Th17 development by altering the balance between STAT5 and STAT3 activation in responding T cells, and provide new insight into how protein citrullination may influence effector Th‐cell development in inflammatory disorders. PMID:27173727

  15. A novel voltammetric sensor based on poly(l-Citrulline)/SWCNTs composite film modified electrode for sensitive determination of picroside II.

    PubMed

    Wang, Wenjing; Wang, Lu; Zou, Lina; Li, Gaiping; Ye, Baoxian

    2016-04-01

    A novel voltammetric sensor was constructed by simple dripping single-walled carbon nanotubes (SWCNTs) on to the glass carbon electrode (GCE) firstly and electro-polymerizing L-Citrulline film subsequently. The resulting poly(L-Citrulline)/SWCNTs/GCE showed a significant voltammetric response to picroside II due to the synergistic effect of SWCNTs and poly(L-Citrulline) film. The first electroanalytical method of picroside II was proposed with detection linear range from 8.0 × 10(-8) to 5.0 × 10(-6) mol L(-1) and a detection limit of 3 × 10(-8) mol L(-1). The high sensitivity, selectivity and long-term stability made the sensor suitable for the determination of picroside II. Moreover, based on the systematically investigation and some kinetics parameters calculated in the experimentation, the reaction mechanism of picroside II at the poly(L-Citrulline)/SWCNTs modified GCE was obtained reliably. Lastly, the proposed sensor was used for the determination of picroside II in real sample with satisfactory results. This work promoted the potential applications of amino acid materials and SWCNTs in electro-chemical sensors. PMID:26838418

  16. Preventing and curing citrulline-induced autoimmune arthritis in a humanized mouse model using a Th2-polarizing iNKT cell agonist.

    PubMed

    Walker, Kyle M; Rytelewski, Mateusz; Mazzuca, Delfina M; Meilleur, Shannon A; Mannik, Lisa A; Yue, David; Brintnell, William C; Welch, Ian; Cairns, Ewa; Haeryfar, S M Mansour

    2012-07-01

    Invariant natural killer T (iNKT) cells are innate lymphocytes with unique reactivity to glycolipid antigens bound to non-polymorphic CD1d molecules. They are capable of rapidly releasing pro- and/or anti-inflammatory cytokines and constitute attractive targets for immunotherapy of a wide range of diseases including autoimmune disorders. In this study, we have explored the beneficial effects of OCH, a Th2-polarizing glycolipid agonist of iNKT cells, in a humanized mouse model of rheumatoid arthritis (RA) in which citrullinated human proteins are targeted by autoaggressive immune responses in mice expressing an RA susceptibility human leukocyte antigen (HLA) DR4 molecule. We found for the first time that treatment with OCH both prevents and cures citrulline-induced autoimmune arthritis as evidenced by resolved ankle swelling and reversed histopathological changes associated with arthritis. Also importantly, OCH treatment blocked the arthritogenic capacity of citrullinated antigen-experienced splenocytes without compromising their global responsiveness or altering the proportion of splenic naturally occurring CD4(+)CD25(+)FoxP3(+) regulatory T cells. Interestingly, administering the Th1-promoting iNKT cell glycolipid ligand α-C-galactosylceramide into HLA-DR4 transgenic mice increased the incidence of arthritis in these animals and exacerbated their clinical symptoms, strongly suggesting a role for Th1 responses in the pathogenesis of citrulline-induced arthritis. Therefore, our findings indicate a role for Th1-mediated immunopathology in citrulline-induced arthritis and provide the first evidence that iNKT cell manipulation by Th2-skewing glycolipids may be of therapeutic value in this clinically relevant model, a finding that is potentially translatable to human RA. PMID:21912419

  17. Anti-citrullinated protein antibodies activated ERK1/2 and JNK mitogen-activated protein kinases via binding to surface-expressed citrullinated GRP78 on mononuclear cells.

    PubMed

    Lu, Ming-Chi; Lai, Ning-Sheng; Yin, Wen-Yao; Yu, Hui-Chun; Huang, Hsien-Bin; Tung, Chien-Hsueh; Huang, Kuang-Yung; Yu, Chia-Li

    2013-04-01

    In a previous study, we found that anti-citrullinated protein antibodies (ACPAs) enhance nuclear factor (NF)-κB activity and tumor necrosis factor (TNF)-α production by normal human peripheral blood mononuclear cells (PBMCs) and U937 cells via binding to surface-expressed citrullinated glucose-regulated protein 78 (cit-GRP78). However, the downstream signaling pathways remain unclear after binding. In the present study, we firstly measured the effects of different kinase inhibitors on ACPA-mediated TNF-α production from normal PBMCs and monocytes. Then, the native and phosphorylated mitogen-activated protein kinases (MAPKs) were detected in ACPA-activated U937 cells by Western blotting. We also explored the role of the phosphoinositide 3-kinase (PI3K)-Akt pathway in activating IκB kinase alpha (IKK-α) in ACPA-stimulated U937 cells. Finally, we measured the amount of cit-GRP78 from PBMC membrane extracts in RA patients and controls. We found that MAPK and Akt inhibitors, but not PI3K inhibitor, remarkably suppressed ACPA-mediated TNF-α production. Interestingly, ACPAs selectively activated extracellular signal-regulated kinase 1/2 (ERK1/2) and c-jun N-terminal kinase (JNK), but not p38 MAPK, in U937 cells. This activation was suppressed by cit-GRP78, but not GRP78. The JNK activation further enhanced the phosphorylation of Akt and IKK-α. The expression of cit-GRP78 on cell membrane was higher in RA than normal PBMCs. Taken together; these results suggest that through binding to surface, over-expressed cit-GRP78 on RA PBMCs, ACPAs selectively activate ERK1/2 and JNK signaling pathways to enhance IKK-α phosphorylation, which leads to the activation of NF-κB and the production of TNF-α . PMID:23188524

  18. Analysis of L-citrulline and L-arginine in Ficus deltoidea leaf extracts by reverse phase high performance liquid chromatography

    PubMed Central

    Shafaei, Armaghan; Aisha, Abdalrahim F. A.; Siddiqui, Mohammad Jamshed Ahmad; Ismail, Zhari

    2015-01-01

    Background: Ficus deltoidea (FD) is one of the native plants widely distributed in several countries in Southeast Asia. Previous studies have shown that FD leaf possess antinociceptive, wound healing and antioxidant properties. These beneficial effects have been attributed to the presence of primary and secondary metabolites such as polyphenols, amino acids and flavonoids. Objective: The aim was to develop a reverse phase high-performance liquid chromatography method with ultraviolet detection that involves precolumn derivatisation with O-phthaladehyde for simultaneous analysis of two amino acids L-citrulline and L-arginine in FD leaf extracts. Materials and Methods: An isocratic elution program consisting of methanol: acetonitrile: Water at 45:45:10 v/v (solvent A) and 0.1 M phosphate buffer pH 7.5 (solvent B) at A: B v/v ratio of 80:20 on Zorbax Eclipse C18 SB-Aq column (250 × 4.6 mm, 5 μm) were used. The flow rate was set at 1 ml/min and detection was carried out at 338 nm with 30 min separation time. Results: Good linearity for L-citrulline and L-arginine was obtained in the range 0.1-1000 μg/ml at R2 ≥ 0.998. The limit of detection and limit of quantification values for both L-citrulline and L-arginine were 1 and 5 μg/ml, respectively. The average of recoveries was in the range 94.94-101.95%, with relative standard deviation (%RSD) less than 3%. Intra- and inter-day precision was in the range 96.36-102.43% with RSD less than 2%. Conclusion: All validation parameters of the developed method indicate the method is reliable and efficient for simultaneous determination of L-citrulline and L-arginine for routine analysis of FD. PMID:25598632

  19. High-performance liquid chromatographic analysis of the unusual pathway of oxidation of L-arginine to citrulline and nitric oxide in mammalian cells.

    PubMed

    Chenais, B; Yapo, A; Lepoivre, M; Tenu, J P

    1991-02-22

    A very unusual pathway of the oxidation of L-arginine to citrulline and nitric oxide has been discovered recently in cytotoxic macrophages. In an attempt to detect molecules generated through this metabolic pathway, a fast radio high-performance liquid chromatographic method was developed to analyse the whole set of radiolabelled L-arginine-derived metabolites produced by mammalian cells after appropriate induction. A new intermediate which might be NG-hydroxy-L-arginine was found. PMID:2045453

  20. Purification and characterization of the human cysteine-rich S100A3 protein and its pseudo citrullinated forms expressed in insect cells.

    PubMed

    Kizawa, Kenji; Unno, Masaki; Takahara, Hidenari; Heizmann, Claus W

    2013-01-01

    High quantity and quality of recombinant Ca(2+)-binding proteins are required to study their molecular interactions, self-assembly, posttranslational modifications, and biological activities to elucidate Ca(2+)-dependent cellular signaling pathways. S100A3 is a unique member of the S100 protein family with the highest cysteine content (10%). This protein, derived from human hair follicles and cuticles, is characterized by an N-terminal acetyl group and irreversible posttranslational citrullination by peptidylarginine deiminase causing its homotetramer assembly. Insect cells, capable of introducing eukaryotic N-terminus and disulfide bonds, are an appropriate host in which to express this cysteine-rich protein. Four out of ten cysteines in the recombinant S100A3 form two intramolecular disulfide bridges that modulate its Ca(2+)-affinity. Three free thiol groups located at the C-terminus are predicted to form the high-affinity Zn(2+)-binding site. Citrullination of specific arginine residues in native S100A3 can be mimicked by site-directed mutagenic substitution of Arg/Ala. This chapter details our procedures used for the purification and characterization of the human S100A3 protein and its pseudo citrullinated forms expressed in insect cells. PMID:23296605

  1. The Role of Citrullinated Protein Antibodies in Predicting Erosive Disease in Rheumatoid Arthritis: A Systematic Literature Review and Meta-Analysis

    PubMed Central

    Jilani, A. A.; Mackworth-Young, C. G.

    2015-01-01

    Background. Autoantibodies to citrullinated peptides have been shown to be valuable in the diagnosis of rheumatoid arthritis (RA). The expanding repertoire of antibodies to citrullinated peptide antigens (ACPA) has been a topic of great interest in recent reviews and research studies, as has the ability of these autoantibodies to predict disease outcome. Objectives. The aim of this review was to provide an update on the relevance of ACPA as prognostic markers in RA. The ability to identify patients predisposed to an aggressive outcome at the time of initial diagnosis greatly facilitates the selection of appropriate and cost-effective treatment. Methods. A systematic review of the literature was carried out. Studies from 1967 up to June 2014 with data on prognostic value of ACPA were included. Quality assessment was done by using the modified Hayden list for prognostic studies. Meta-analysis was performed using BioStat software. Results. The results of 25 studies were selected for the final review. A total of 6421 patients with RA were included, mainly in inception cohorts, with follow-up duration ranging from one year to ten years. All studies carried prognostic data on all available isotypes of anticyclic citrullinated protein (CCP), while four had data on antimutated citrullinated vimentin (MCV). There was a single relevant study each on anticitrullinated enolase peptide 1 (CEP1) and antichimaeric fibrin/filaggrin citrullinated peptide 1 (CFFCP1). All studies showed ACPA to be strong predictors of joint erosions in RA. Other factors, particularly baseline erosions, showed an additive effect. Anti-MCV appeared to be a marker of a more aggressive form of disease. Ten studies had data on which a meta-analysis could be performed. This gave an overall odds ratio of 4.85 for ACPA (anti-CCP/MCV) positivity being predictive for the development of joint erosions. Two studies with data on anti-CEP1 and anti-CFFCP1 also showed this positive predictive role of ACPA for joint

  2. Presence of Citrullinated Histone H3-Positive Neutrophils in Microscopic Polyangiitis from the Early Phase: An Autopsy Proven Case.

    PubMed

    Matsuda, Yoko; Hamayasu, Hideki; Seki, Atsuko; Nonaka, Keisuke; Wang, Tan; Matsumoto, Takumi; Hamano, Yoshitomo; Sumikura, Hiroyuki; Kumasaka, Toshio; Murayama, Shigeo; Ishizu, Akihiko; Shimizu, Akira; Sugihara, Takahiko; Arai, Tomio

    2016-08-01

    A 76-year-old man was admitted with general fatigue, weight loss, fever, headache, renal failure, and a high serum level of myeloperoxidase-antineutrophil cytoplasmic antibody. Biopsy revealed citrullinated histone H3 (citH3)-positive neutrophils adherent to the temporal artery endothelium. Three days after completing pulse steroid therapy, he suffered from a sudden disturbance of consciousness and died. On autopsy, the kidneys showed the most severe vasculitis with dense infiltration of citH3-positive neutrophils. The lungs showed intra-alveolar hemorrhage due to capillaritis. Severe brain hemorrhage was found in the left frontal lobe and putamen with uncal herniation. No vasculitis or thrombi was observed in the brain. The right dura mater was thickened due to fibrosis and inflammation. In conclusion, autopsy revealed systemic vasculitis with infiltration of abundant citH3-positive neutrophils, suggesting that the neutrophil extracellular trap formation and citH3 might play important roles in the early phases and development of microscopic polyangiitis. PMID:27427341

  3. Supporting data for the MS identification of distinct transferrin glycopeptide glycoforms and citrullinated peptides associated with inflammation or autoimmunity

    PubMed Central

    Rosal-Vela, A.; Barroso, A.; Giménez, E.; García-Rodríguez, S.; Longobardo, V.; Postigo, J.; Iglesias, M.; Lario, A.; Merino, J.; Merino, R.; Zubiaur, M.; Sanz-Nebot, V.; Sancho, J.

    2016-01-01

    This data article presents the results of all the statistical analyses applied to the relative intensities of the detected 2D-DiGE protein spots for each of the 3 performed DiGE experiments. The data reveals specific subsets of protein spots with significant differences between WT and CD38-deficient mice with either Collagen-induced arthritis (CIA), or with chronic inflammation induced by CFA, or under steady-state conditions. This article also shows the MS data analyses that allowed the identification of the protein species which serve to discriminate the different experimental groups used in this study. Moreover, the article presents MS data on the citrullinated peptides linked to specific protein species that were generated in CIA+ or CFA-treated mice. Lastly, this data article provides MS data on the efficiency of the analyses of the transferrin (Tf) glycopeptide glycosylation pattern in spleen and serum from CIA+ mice and normal controls. The data supplied in this work is related to the research article entitled “identification of multiple transferrin species in spleen and serum from mice with collagen-induced arthritis which may reflect changes in transferrin glycosylation associated with disease activity: the role of CD38” [1]. All mass spectrometry data have been deposited to the ProteomeXchange Consortium via the PRIDE partner repository with identifiers PRIDE: PXD002644, PRIDE: PXD002643, PRIDE: PXD003183 and PRIDE: PXD003163. PMID:26909372

  4. Molecular Basis of Valine-Citrulline-PABC Linker Instability in Site-Specific ADCs and Its Mitigation by Linker Design.

    PubMed

    Dorywalska, Magdalena; Dushin, Russell; Moine, Ludivine; Farias, Santiago E; Zhou, Dahui; Navaratnam, Thayalan; Lui, Victor; Hasa-Moreno, Adela; Casas, Meritxell Galindo; Tran, Thomas-Toan; Delaria, Kathy; Liu, Shu-Hui; Foletti, Davide; O'Donnell, Christopher J; Pons, Jaume; Shelton, David L; Rajpal, Arvind; Strop, Pavel

    2016-05-01

    The degree of stability of antibody-drug linkers in systemic circulation, and the rate of their intracellular processing within target cancer cells are among the key factors determining the efficacy of antibody-drug conjugates (ADC) in vivo Previous studies demonstrated the susceptibility of cleavable linkers, as well as auristatin-based payloads, to enzymatic cleavage in rodent plasma. Here, we identify Carboxylesterase 1C as the enzyme responsible for the extracellular hydrolysis of valine-citrulline-p-aminocarbamate (VC-PABC)-based linkers in mouse plasma. We further show that the activity of Carboxylesterase 1C towards VC-PABC-based linkers, and consequently the stability of ADCs in mouse plasma, can be effectively modulated by small chemical modifications to the linker. While the introduced modifications can protect the VC-PABC-based linkers from extracellular cleavage, they do not significantly alter the intracellular linker processing by the lysosomal protease Cathepsin B. The distinct substrate preference of the serum Carboxylesterase 1C offers the opportunity to modulate the extracellular stability of cleavable ADCs without diminishing the intracellular payload release required for ADC efficacy. Mol Cancer Ther; 15(5); 958-70. ©2016 AACR. PMID:26944918

  5. Supporting data for the MS identification of distinct transferrin glycopeptide glycoforms and citrullinated peptides associated with inflammation or autoimmunity.

    PubMed

    Rosal-Vela, A; Barroso, A; Giménez, E; García-Rodríguez, S; Longobardo, V; Postigo, J; Iglesias, M; Lario, A; Merino, J; Merino, R; Zubiaur, M; Sanz-Nebot, V; Sancho, J

    2016-03-01

    This data article presents the results of all the statistical analyses applied to the relative intensities of the detected 2D-DiGE protein spots for each of the 3 performed DiGE experiments. The data reveals specific subsets of protein spots with significant differences between WT and CD38-deficient mice with either Collagen-induced arthritis (CIA), or with chronic inflammation induced by CFA, or under steady-state conditions. This article also shows the MS data analyses that allowed the identification of the protein species which serve to discriminate the different experimental groups used in this study. Moreover, the article presents MS data on the citrullinated peptides linked to specific protein species that were generated in CIA(+) or CFA-treated mice. Lastly, this data article provides MS data on the efficiency of the analyses of the transferrin (Tf) glycopeptide glycosylation pattern in spleen and serum from CIA(+) mice and normal controls. The data supplied in this work is related to the research article entitled "identification of multiple transferrin species in spleen and serum from mice with collagen-induced arthritis which may reflect changes in transferrin glycosylation associated with disease activity: the role of CD38" [1]. All mass spectrometry data have been deposited to the ProteomeXchange Consortium via the PRIDE partner repository with identifiers PRIDE: PXD002644, PRIDE: PXD002643, PRIDE: PXD003183 and PRIDE: PXD003163. PMID:26909372

  6. Significant association of periodontal disease with anti-citrullinated peptide antibody in a Japanese healthy population - The Nagahama study.

    PubMed

    Terao, Chikashi; Asai, Keita; Hashimoto, Motomu; Yamazaki, Toru; Ohmura, Koichiro; Yamaguchi, Akihiko; Takahashi, Katsu; Takei, Noriko; Ishii, Takanori; Kawaguchi, Takahisa; Tabara, Yasuharu; Takahashi, Meiko; Nakayama, Takeo; Kosugi, Shinji; Sekine, Akihiro; Fujii, Takao; Yamada, Ryo; Mimori, Tsuneyo; Matsuda, Fumihiko; Bessho, Kazuhisa

    2015-05-01

    Anti-citrullinated peptide antibody (ACPA) is a highly specific autoantibody to rheumatoid arthritis (RA). Recent studies have revealed that periodontal disease (PD) is closely associated with RA and production of ACPA in RA. Analyses of associations between PD and ACPA production in a healthy population may deepen our understandings. Here, we analyzed a total of 9554 adult healthy subjects. ACPA and IgM-rheumatoid factor (RF) was quantified and PD status was evaluated using the number of missing teeth (MT), the Community Periodontal Index (CPI) and Loss of Attachment (LA) for these subjects. PD status was analyzed for its association with the positivity and categorical levels of ACPA and RF conditioned for covariates which were shown to be associated with PD, ACPA or RF. As a result, all of MT, CPI and LA showed suggestive or significant associations with positivity (p = 0.024, 0.0042 and 0.037, respectively) and levels of ACPA (p ≤ 0.00031), but none of the PD parameters were associated with those of RF. These association patterns were also observed when we analyzed 6206 non-smokers of the participants. The significant associations between PD parameters and positivity and levels of ACPA in healthy population support the fundamental involvement of PD with ACPA production. PMID:25819755

  7. Prevalence of autoantibodies to cyclic citrullinated peptide in patients with rheumatic diseases other than rheumatoid arthritis: a French multicenter study.

    PubMed

    Fabien, Nicole; Olsson, Nils-Olivier; Goetz, Joëlle; Johanet, Catherine; Escande, Andrée; Bardin, Nathalie; Sanmarco, Marielle; Andre, Chantal; Chevailler, Alain; Humbel, René-Louis; Chretien, Pascale; Monier, Jean-claude; Fortenfant, Françoise; Oksman, Françoise; Taillefer, Marie-France; Sibilia, Jean

    2008-02-01

    Our objective was to evaluate the prevalence of autoantibodies to cyclic citrullinated peptides (anti-CCP aAbs) in a cohort of patients with a variety of inflammatory or non-inflammatory rheumatic diseases other than rheumatoid arthritis (RA). Six hundred and nine serum samples were tested for anti-CCP aAbs and for rheumatoid factor (RF) using enzyme-linked immunosorbent assays and immunonephelometry. The prevalence of anti-CCP aAbs and RF reached 10% and 25%, respectively, using the positive cutoff value suggested by the manufacturers. Using a higher cutoff value (50 U/ml) for both aAbs, the prevalence was lower with 6% and 16%, respectively. The specificity of both markers for RA thus reached 94% and 84%, respectively. Anti-CCP aAbs were found to be elevated in inflammatory and also in non-inflammatory rheumatic diseases in the same proportion. Clinical data obtained for 36 positive patients showed that 17% developed RA within 5 years. In conclusion, anti-CCP aAbs are clearly more specific than RF for RA. Follow-up of anti-CCP aAbs-positive patients with inflammatory or non-inflammatory rheumatic diseases other than RA could be important considering the predictive value of these aAbs for the development of RA. PMID:18247159

  8. Anti citrullinated protein antibodies and mechanism of action of common disease modifying drugs--insights in pathomechanisms of autoimmunity.

    PubMed

    Pongratz, Georg; Fleck, Martin

    2012-01-01

    The increasing understanding of autoimmune mechanisms continuously leads to new therapeutic targets and development of novel diagnostic tools in rheumatology. On the other hand, an improved comprehension of mechanisms of action of many drugs and the daily utilization in rheumatology leads to a better understanding of the underlying autoimmune processes. An example for the latter is Bcell depletion using anti-CD20 antibodies, which leads to the concept of B cells not only playing a role as antibody secreting cells but also as important cellular components of autoimmune processes, acting as antigen presenting and cytokine producing cells. Another example is the conventional disease modifying anti-rheumatic drug methotrexate, which has also been used successfully in the clinic first and then, while trying to understand its mechanism of action, led to knew insights in autoimmune mechanisms e.g. revealing the strong anti-inflammatory potential of adenosine. But not only the mechanism of action of different drugs, but also the identification of antibodies against citrullinated proteins (ACPA) as a valuable diagnostic tool resulted in novel concepts regarding the pathophysiology of rheumatoid arthritis. The following review first explains the value of ACPA in the diagnosis of rheumatoid arthritis (RA) and then summarizes the application and mechanism of action of several important substances used in the management of autoimmune disorders. Based on these insights, the authors explain their understanding of the autoimmune process as a continuous repeat of autoantigen presentation - autoreactive effector cell activation - destruction of tissue - liberation of new autoantigens - and again autoantigen presentation, which closes the vicious circle. PMID:22612739

  9. Preventive effects of citrulline on Western diet-induced non-alcoholic fatty liver disease in rats.

    PubMed

    Jegatheesan, Prasanthi; Beutheu, Stéphanie; Freese, Kim; Waligora-Dupriet, Anne-Judith; Nubret, Esther; Butel, Marie-Jo; Bergheim, Ina; De Bandt, Jean-Pascal

    2016-07-01

    A Western diet induces insulin resistance, liver steatosis (non-alcoholic fatty liver disease (NAFLD)) and intestinal dysbiosis, leading to increased gut permeability and bacterial translocation, thus contributing to the progression of NAFLD to non-alcoholic steatohepatitis. In the present study, we sought, in a model of Western diet-induced NAFLD, to determine whether citrulline (Cit), an amino acid that regulates protein and energy metabolism, could decrease Western diet-induced liver injuries, as well as the mechanisms involved. Sprague-Dawley rats were fed a high-fat diet (45 %) and fructose (30 %) in drinking water or a control diet associated with water (group C) for 8 weeks. The high-fat, high-fructose diet (Western diet) was fed either alone (group WD) or with Cit (1 g/kg per d) (group WDC) or an isonitrogenous amount of non-essential amino acids (group WDA). We evaluated nutritional and metabolic status, liver function, intestinal barrier function, gut microbiota and splanchnic inflammatory status. Cit led to a lower level of hepatic TAG restricted to microvesicular lipid droplets and to a lower mRNA expression of CCAAT-enhancer-binding protein homologous protein, a marker of endoplasmic reticulum stress, of pro-inflammatory cytokines Il6 (P<0·05) and Tnfα, and of toll-like receptor 4 (Tlr4) (P<0·05). Cit also improved plasma TAG and insulin levels. In the colon, it decreased inflammation (Tnfα and Tlr4 expressions) and increased claudin-1 protein expression. This was associated with higher levels of Bacteroides/Prevotella compared with rats fed the Western diet alone. Cit improves Western diet-induced liver injuries via decreased lipid deposition, increased insulin sensitivity, lower inflammatory process and preserved antioxidant status. This may be related in part to its protective effects at the gut level. PMID:27197843

  10. Quantitative Metabolomic Analysis of Urinary Citrulline and Calcitroic Acid in Mice after Exposure to Various Types of Ionizing Radiation

    PubMed Central

    Goudarzi, Maryam; Chauthe, Siddheshwar; Strawn, Steven J.; Weber, Waylon M.; Brenner, David J.; Fornace, Albert J.

    2016-01-01

    With the safety of existing nuclear power plants being brought into question after the Fukushima disaster and the increased level of concern over terrorism-sponsored use of improvised nuclear devices, it is more crucial to develop well-defined radiation injury markers in easily accessible biofluids to help emergency-responders with injury assessment during patient triage. Here, we focused on utilizing ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to identify and quantitate the unique changes in the urinary excretion of two metabolite markers, calcitroic acid and citrulline, in mice induced by different forms of irradiation; X-ray irradiation at a low dose rate (LDR) of 3.0 mGy/min and a high dose rate (HDR) of 1.1 Gy/min, and internal exposure to Cesium-137 (137Cs) and Strontium-90 (90Sr). The multiple reaction monitoring analysis showed that, while exposure to 137Cs and 90Sr induced a statistically significant and persistent decrease, similar doses of X-ray beam at the HDR had the opposite effect, and the LDR had no effect on the urinary levels of these two metabolites. This suggests that the source of exposure and the dose rate strongly modulate the in vivo metabolomic injury responses, which may have utility in clinical biodosimetry assays for the assessment of exposure in an affected population. This study complements our previous investigations into the metabolomic profile of urine from mice internally exposed to 90Sr and 137Cs and to X-ray beam radiation. PMID:27213362

  11. Quantitative Metabolomic Analysis of Urinary Citrulline and Calcitroic Acid in Mice after Exposure to Various Types of Ionizing Radiation.

    PubMed

    Goudarzi, Maryam; Chauthe, Siddheshwar; Strawn, Steven J; Weber, Waylon M; Brenner, David J; Fornace, Albert J

    2016-01-01

    With the safety of existing nuclear power plants being brought into question after the Fukushima disaster and the increased level of concern over terrorism-sponsored use of improvised nuclear devices, it is more crucial to develop well-defined radiation injury markers in easily accessible biofluids to help emergency-responders with injury assessment during patient triage. Here, we focused on utilizing ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to identify and quantitate the unique changes in the urinary excretion of two metabolite markers, calcitroic acid and citrulline, in mice induced by different forms of irradiation; external γ irradiation at a low dose rate (LDR) of 3.0 mGy/min and a high dose rate (HDR) of 1.1 Gy/min, and internal exposure to Cesium-137 ((137)Cs) and Strontium-90 ((90)Sr). The multiple reaction monitoring analysis showed that, while exposure to (137)Cs and (90)Sr induced a statistically significant and persistent decrease, similar doses of external γ beam at the HDR had the opposite effect, and the LDR had no effect on the urinary levels of these two metabolites. This suggests that the source of exposure and the dose rate strongly modulate the in vivo metabolomic injury responses, which may have utility in clinical biodosimetry assays for the assessment of exposure in an affected population. This study complements our previous investigations into the metabolomic profile of urine from mice internally exposed to (90)Sr and (137)Cs and to external γ beam radiation. PMID:27213362

  12. Effects of type II collagen epitope carbamylation and citrullination in human leucocyte antigen (HLA)-DR4(+) monozygotic twins discordant for rheumatoid arthritis.

    PubMed

    De Santis, M; Ceribelli, A; Cavaciocchi, F; Generali, E; Massarotti, M; Isailovic, N; Crotti, C; Scherer, H U; Montecucco, C; Selmi, C

    2016-09-01

    The aim of this study is to investigate the effect of the native, citrullinated or carbamylated type II human collagen T cell- and B cell-epitopes on the adaptive immune response in rheumatoid arthritis (RA). Peripheral blood T and B cells obtained from a human leucocyte D4-related (antigen DR4(-) HLA-DR4)(+) woman with early RA, her healthy monozygotic twin and an unrelated HLA-DR3(+) woman with early RA were analysed for activation (CD154/CD69), apoptosis (annexin/7-aminoactinomycin), cytokine production [interferon (IFN)γ/interleukin (IL)-17/IL-4/IL-10/IL-6] and functional phenotype (CD45Ra/CCR7) after stimulation with the collagen native T cell epitope (T261-273), the K264 carbamylated T cell epitope (carT261-273), the native B cell epitope (B359-369) or the R360 citrullinated B cell epitope (citB359-369), and the combinations of these. The T cell memory compartment was activated by T cell epitopes in both discordant DR4(+) twins, but not in the DR3(+) RA. The collagen-specific activation of CD4(+) T cells was induced with both the native and carbamylated T cell epitopes only in the RA twin. Both T cell epitopes also induced IL-17 production in the RA twin, but a greater IL-4 and IL-10 response in the healthy twin. The citrullinated B cell epitope, particularly when combined with the carbamylated T cell epitope, induced B cell activation and an increased IL-6/IL-10 ratio in the RA twin compared to a greater IL-10 production in the healthy twin. Our data suggest that circulating collagen-specific T and B cells are found in HLA-DR4(+) subjects, but only RA activated cells express co-stimulatory molecules and produce proinflammatory cytokines. Carbamylation and citrullination further modulate the activation and cytokine polarization of T and B cells. PMID:27314557

  13. Nitric oxide (NO), citrulline-NO cycle enzymes, glutamine synthetase, and oxidative status in kainic acid-mediated excitotoxicity in rat brain.

    PubMed

    Swamy, Mummedy; Sirajudeen, Kuttulebbai N S; Chandran, Govindasamy

    2009-01-01

    Neuronal excitation, involving the excitatory glutamate receptors, is recognized as an important underlying mechanism in neurodegenerative disorders. To understand their role in excitotoxicity, the nitric oxide synthase (NOS), argininosuccinate synthetase (AS), argininosuccinate lyase (AL), glutamine synthetase (GS), and arginase activities, along with the concentration of nitrate/nitrite, thiobarbituric acid-reactive substances (TBARS), and total antioxidant status (TAS), were estimated in the cerebral cortex, cerebellum, and brain stem of rats subjected to kainic acid-mediated excitotoxicity. The results of this study clearly demonstrated the increased production of NO by increased activity of NOS. The increased activities of AS and AL suggest the increased and effective recycling of citrulline to arginine in excitotoxicity, making NO production more effective and contributing to its toxic effects. The decreased activity of GS may favor the prolonged availability of glutamic acid, causing excitotoxicity, leading to neuronal damage. The increased formation of TBARS and decreased TAS indicate the presence of oxidative stress in excitotoxicity. PMID:19793024

  14. Acute induction of uncoupling protein 1 by citrulline in cultured explants of white adipose tissue from lean and high-fat-diet-fed rats

    PubMed Central

    Joffin, Nolwenn; Jaubert, Anne-Marie; Bamba, Jessica; Barouki, Robert; Noirez, Philippe; Forest, Claude

    2015-01-01

    A diet enriched with citrulline (CIT) reduces white adipose tissue (WAT) mass. We recently showed that CIT stimulated β-oxidation in rat WAT explants from young (2–4 months) but not old (25 months) rats. Here we show that both in old rats and high-fat-diet-fed young rats, uncoupling protein one (UCP1) mRNA and protein expressions were weaker than those in young control rats. Selectively in WAT from young rats, a 24h CIT treatment up-regulated expressions of UCP1, peroxisome proliferator-activated receptor-α (PPARα), PPARγ-coactivator-1-α and mitochondrial-transcription-factor-A whereas it down-regulated PPARγ2 gene expression, whatever the diet. These results suggest that CIT induces a new metabolic status in WAT, with increased β-oxidation and uncoupling of respiratory chain, resulting in energy expenditure that favors fat mass reduction. PMID:26167416

  15. Arginine methylation and citrullination of splicing factor proline- and glutamine-rich (SFPQ/PSF) regulates its association with mRNA

    PubMed Central

    Snijders, Ambrosius P.; Hautbergue, Guillaume M.; Bloom, Alex; Williamson, James C.; Minshull, Thomas C.; Phillips, Helen L.; Mihaylov, Simeon R.; Gjerde, Douglas T.; Hornby, David P.; Wilson, Stuart A.; Hurd, Paul J.

    2015-01-01

    Splicing factor proline- and glutamine-rich (SFPQ) also commonly known as polypyrimidine tract-binding protein-associated-splicing factor (PSF) and its binding partner non-POU domain-containing octamer-binding protein (NONO/p54nrb), are highly abundant, multifunctional nuclear proteins. However, the exact role of this complex is yet to be determined. Following purification of the endogeneous SFPQ/NONO complex, mass spectrometry analysis identified a wide range of interacting proteins, including those involved in RNA processing, RNA splicing, and transcriptional regulation, consistent with a multifunctional role for SFPQ/NONO. In addition, we have identified several sites of arginine methylation in SFPQ/PSF using mass spectrometry and found that several arginines in the N-terminal domain of SFPQ/PSF are asymmetrically dimethylated. Furthermore, we find that the protein arginine N-methyltransferase, PRMT1, catalyzes this methylation in vitro and that this is antagonized by citrullination of SFPQ. Arginine methylation and citrullination of SFPQ/PSF does not affect complex formation with NONO. However, arginine methylation was shown to increase the association with mRNA in mRNP complexes in mammalian cells. Finally we show that the biochemical properties of the endogenous complex from cell lysates are significantly influenced by the ionic strength during purification. At low ionic strength, the SFPQ/NONO complex forms large heterogeneous protein assemblies or aggregates, preventing the purification of the SFPQ/NONO complex. The ability of the SFPQ/NONO complex to form varying protein assemblies, in conjunction with the effect of post-translational modifications of SFPQ modulating mRNA binding, suggests key roles affecting mRNP dynamics within the cell. PMID:25605962

  16. Nitric oxide (no), citrulline - no cycle enzymes, glutamine synthetase and oxidative stress in anoxia (hypobaric hypoxia) and reperfusion in rat brain.

    PubMed

    Swamy, M; Salleh, Mohd Jamsani Mat; Sirajudeen, K N S; Yusof, Wan Roslina Wan; Chandran, G

    2010-01-01

    Nitric oxide is postulated to be involved in the pathophysiology of neurological disorders due to hypoxia/ anoxia in brain due to increased release of glutamate and activation of N-methyl-D-aspartate receptors. Reactive oxygen species have been implicated in pathophysiology of many neurological disorders and in brain function. To understand their role in anoxia (hypobaric hypoxia) and reperfusion (reoxygenation), the nitric oxide synthase, argininosuccinate synthetase, argininosuccinate lyase, glutamine synthetase and arginase activities along with the concentration of nitrate /nitrite, thiobarbituric acid reactive substances and total antioxidant status were estimated in cerebral cortex, cerebellum and brain stem of rats subjected to anoxia and reperfusion. The results of this study clearly demonstrated the increased production of nitric oxide by increased activity of nitric oxide synthase. The increased activities of argininosuccinate synthetase and argininosuccinate lyase suggest the increased and effective recycling of citrulline to arginine in anoxia, making nitric oxide production more effective and contributing to its toxic effects. The decreased activity of glutamine synthetase may favor the prolonged availability of glutamic acid causing excitotoxicity leading to neuronal damage in anoxia. The increased formation of thiobarbituric acid reactive substances and decreased total antioxidant status indicate the presence of oxidative stress in anoxia and reperfusion. The increased arginase and sustained decrease of GS activity in reperfusion group likely to be protective. PMID:20567615

  17. l-Citrulline supplementation attenuates blood pressure, wave reflection and arterial stiffness responses to metaboreflex and cold stress in overweight men.

    PubMed

    Figueroa, Arturo; Alvarez-Alvarado, Stacey; Jaime, Salvador J; Kalfon, Roy

    2016-07-01

    Combined isometric exercise or metaboreflex activation (post-exercise muscle ischaemia (PEMI)) and cold pressor test (CPT) increase cardiac afterload, which may lead to adverse cardiovascular events. l-Citrulline supplementation (l-CIT) reduces systemic arterial stiffness (brachial-ankle pulse wave velocity (baPWV)) at rest and aortic haemodynamic responses to CPT. The aim of this study was to determine the effect of l-CIT on aortic haemodynamic and baPWV responses to PEMI+CPT. In all, sixteen healthy, overweight/obese males (age 24 (sem 6) years; BMI 29·3 (sem 4·0) kg/m2) were randomly assigned to placebo or l-CIT (6 g/d) for 14 d in a cross-over design. Brachial and aortic systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP), aortic augmented pressure (AP), augmentation index (AIx), baPWV, reflection timing (Tr) and heart rate (HR) were evaluated at rest and during isometric handgrip exercise (IHG), PEMI and PEMI+CPT at baseline and after 14 d. No significant effects were evident after l-CIT at rest. l-CIT attenuated the increases in aortic SBP and wave reflection (AP and AIx) during IHG, aortic DBP, MAP and AIx during PEMI, and aortic SBP, DBP, MAP, AP, AIx and baPWV during PEMI+CPT compared with placebo. HR and Tr were unaffected by l-CIT in all conditions. Our findings demonstrate that l-CIT attenuates aortic blood pressure and wave reflection responses to exercise-related metabolites. Moreover, l-CIT attenuates the exaggerated arterial stiffness response to combined metaboreflex activation and cold exposure, suggesting a protective effect against increased cardiac afterload during physical stress. PMID:27160957

  18. Decreased glutamine synthetase, increased citrulline-nitric oxide cycle activities, and oxidative stress in different regions of brain in epilepsy rat model.

    PubMed

    Swamy, Mummedy; Yusof, Wan Roslina Wan; Sirajudeen, K N S; Mustapha, Zulkarnain; Govindasamy, Chandran

    2011-03-01

    To understand their role in epilepsy, the nitric oxide synthetase (NOS), argininosuccinate synthetase (AS), argininosuccinate lyase (AL), glutamine synthetase (GS), and arginase activities, along with the concentration of nitrate/nitrite (NOx), thiobarbituric acid reactive substances (TBARS), and total antioxidant status (TAS), were estimated in different regions of brain in rats subjected to experimental epilepsy induced by subcutaneous administration of kainic acid (KA). The short-term (acute) group animals were killed after 2 h and the long term (chronic) group animals were killed after 5 days of single injection of KA (15 mg/kg body weight). After decapitation of rats, the brain regions were separated and in their homogenates, the concentration of NOx, TBARS and TAS and the activities of NOS, AS, AL, arginase and glutamine synthetase were assayed by colorimetric methods. The results of the study demonstrated the increased activity of NOS and formation of NO in acute and chronic groups epilepsy. The activities of AS and AL were increased and indicate the effective recycling of citrulline to arginine. The activity of glutamine synthetase was decreased in acute and chronic groups of epilepsy compared to control group and indicate the modulation of its activity by NO in epilepsy. The activity of arginase was not changed in acute group; however it was decreased in chronic group and may favor increased production of NO in this condition. The concentration TBARS were increased and TAS decreased in acute and chronic groups of epilepsy and supports the oxidative stress in epilepsy. PMID:20960085

  19. Unfolded protein response gene GADD34 is overexpressed in rheumatoid arthritis and related to the presence of circulating anti-citrullinated protein antibodies.

    PubMed

    Clavarino, Giovanna; Adriouach, Souad; Quesada, Jean-Louis; Clay, Marine; Chevreau, Maxime; Trocmé, Candice; Grange, Laurent; Gaudin, Philippe; Gatti, Evelina; Pierre, Philippe; Cesbron, Jean-Yves; Dumestre-Pérard, Chantal

    2016-05-01

    Growth arrest and DNA damage-inducible gene 34 (GADD34) is an inducible cofactor of protein phosphatase 1, which has an important role in the unfolded protein response. GADD34 has been shown to be necessary for type I interferon and proinflammatory cytokine production in response to viral infection in murine models. We investigate the expression of GADD34 in rheumatoid arthritis (RA), in which proinflammatory cytokines have an important pathogenic role. The objective of this study was to evaluate the potential of GADD34 expression as a biomarker in RA patients. We report a case-control study on GADD34 gene expression in peripheral blood mononuclear cells of patients (n = 75) with RA and age- and sex-matched healthy controls (n = 25). The study was approved by the relevant local ethics committees. GADD34 gene expression level in peripheral blood mononuclear cells was measured by quantitative PCR and analyzed with Mann-Whitney test. The relation between GADD34 gene overexpression and clinical or biological characteristics was analyzed with univariate and multivariate analysis. GADD34 gene expression was significantly higher in RA patients compared with healthy controls (p ≤ 0.001). Interestingly, GADD34 overexpression in PBMC of patients was related to the presence of circulating anti-citrullinated protein antibodies (p = 0.030). Data of this study strengthen the evidence of an unfolded protein response during the course of RA and provide an insight of the potential interest in GADD34 as a relevant marker for RA. PMID:26829377

  20. Treatment with a combination of ginger, L-citrulline, muira puama and Paullinia cupana can reverse the progression of corporal smooth muscle loss, fibrosis and veno-occlusive dysfunction in the aging rat

    PubMed Central

    Ferrini, Monica G.; Hlaing, Su M.; Chan, Andre; Artaza, Jorge N.

    2015-01-01

    Aims Aging associated erectile dysfunction is characterized within the corpora by a progressive apoptosis of the smooth muscle cells and their replacement by collagen. Nitric oxide from iNOS has been shown to inhibit these histological changes in the corpora while PDE5 inhibitors as well as certain nutraceuticals such as ginger, paullinia cupana, muira puama and L-citrulline are known to enhance the effects of NO. We evaluated whether the daily oral administration for 2 months with a combination of ginger, paullinia cupana, muira puama and L-citrulline (COMP-4) can effectively delay the ongoing corporal fibrosis, smooth muscle cell apoptosis and cavernosal veno-occlusive dysfunction (CVOD) seen in middle aged rats similar to that seen with tadalafil. Methods 10 Month old Fisher 344 rats were treated or not for two months with COMP-4, tadalafil or a combination of tadalafil plus COMP-4. CVOD was determined by dynamic infusion cavernosometry. Penile sections of the corpora cavernosa were subjected to Masson trichrome staining to evaluate fibrosis and immunohistochemistry for desmin as a marker of smooth muscle content and inducible nitric oxide synthase (iNOS) followed by image analysis. Oxidative stress levels were determined by GSH/GSSG ratio in whole blood. Results a decline in the non-treated rat's erectile function is evident by 10-12 months of age and is accompanied by a decrease in the corporal smooth muscle content determined by desmin expression and an increase in corporal fibrosis. The daily treatment for two months with COMP-4 reverses this process by reducing systemic oxidative stress and increasing desmin and iNOS expression, similar to that seen with tadalafil or the combination of COMP-4 plus tadalafil. Conclusion An oral combination of ginger, muira puama, Paullinia cupana and L-citrulline seems to be as effective as daily PDE5 inhibitor therapy in either delaying or reversing the onset of the histological and functional characteristics of aging

  1. Predictive value of autoantibodies from anti-CCP2, anti-MCV and anti-human citrullinated fibrinogen tests, in early rheumatoid arthritis patients with rapid radiographic progression at 1 year: results from the ESPOIR cohort

    PubMed Central

    Degboé, Yannick; Constantin, Arnaud; Nigon, Delphine; Tobon, Gabriel; Cornillet, Martin; Schaeverbeke, Thierry; Chiocchia, Gilles; Nicaise-Roland, Pascale; Nogueira, Leonor; Serre, Guy; Cantagrel, Alain; Ruyssen-Witrand, Adeline

    2015-01-01

    Objectives We compared the ability of antibodies against cyclic citrullinated peptides (anti-CCP2), against mutated citrullinated vimentin (anti-MCV) and against citrullinated fibrinogen (AhFibA) to predict 1 year rapid radiographic progression (RRP; total Sharp score variation ≥5 points), in early rheumatoid arthritis (RA). Methods We analysed 566 patients from the ESPOIR cohort with early RA fulfilling the 2010 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) criteria at year 1. We assayed the 3 anticitrullinated peptide antibodies (ACPA) tests on baseline sera. We compared the performance of these 3 ACPA tests to predict first-year RRP, by comparing areas under the receiver operating characteristic curves (ROCs). We assessed the 1 year RRP risk by ACPA titres. We used a logistic multivariate regression to analyse RRP risk in terms either of ACPA positivity or titre: high (>3 times the N cut-off) and low (1 to 3N). Results 145 patients displayed RRP. Areas under the ROCs were similar (0.60) for the 3 tests. High ACPA titres were associated with 1 year RRP, whatever the test was, and with similar ORs. Low+ anti-MCV titres were not associated with 1-year RRP, whereas low+ anti-CCP2 titres (p=0.0226) and low+ AhFibA titres (p=0.0332) were significantly associated. In multivariate analysis, 1 year RRP was associated with anti-CCP2 positivity (p<0.0001), AhFibA positivity (p<0.0001) and high anti-MCV titres (p<0.0001). Conclusions Anti-CCP2 antibodies and AhFibA were predictive of 1 year RRP in early RA whatever their titre was, whereas only high anti-MCV antibody titres were predictive, potentially making them more discriminant to predict 1 year RRP risk. PMID:26635969

  2. Replication of Associations of Genetic Loci Outside the HLA Region With Susceptibility to Anti–Cyclic Citrullinated Peptide–Negative Rheumatoid Arthritis

    PubMed Central

    Viatte, Sebastien; Massey, Jonathan; Bowes, John; Duffus, Kate; Eyre, Stephen; Barton, Anne; Loughlin, John; Arden, Nigel; Birrell, Fraser; Carr, Andrew; Deloukas, Panos; Doherty, Michael; McCaskie, Andrew W.; Ollier, William E. R.; Rai, Ashok; Ralston, Stuart H.; Spector, Tim D.; Valdes, Ana M.; Wallis, Gillian A.; Wilkinson, J. Mark; Zeggini, Eleftheria

    2016-01-01

    Objective Genetic polymorphisms within the HLA region explain only a modest proportion of anti–cyclic citrullinated peptide (anti‐CCP)–negative rheumatoid arthritis (RA) heritability. However, few non‐HLA markers have been identified so far. This study was undertaken to replicate the associations of anti‐CCP–negative RA with non‐HLA genetic polymorphisms demonstrated in a previous study. Methods The Rheumatoid Arthritis Consortium International densely genotyped 186 autoimmune‐related regions in 3,339 anti‐CCP–negative RA patients and 15,870 controls across 6 different populations using the Illumina ImmunoChip array. We performed a case–control replication study of the anti‐CCP–negative markers with the strongest associations in that discovery study, in an independent cohort of anti‐CCP–negative UK RA patients. Individuals from the arcOGEN Consortium and Wellcome Trust Case Control Consortium were used as controls. Genotyping in cases was performed using Sequenom MassArray technology. Genome‐wide data from controls were imputed using the 1000 Genomes Phase I integrated variant call set release version 3 as a reference panel. Results After genotyping and imputation quality control procedures, data were available for 15 non‐HLA single‐nucleotide polymorphisms in 1,024 cases and 6,348 controls. We confirmed the known markers ANKRD55 (meta‐analysis odds ratio [OR] 0.80; P = 2.8 × 10−13) and BLK (OR 1.13; P = 7.0 × 10−6) and identified new and specific markers of anti‐CCP–negative RA (prolactin [PRL] [OR 1.13; P = 2.1 × 10−6] and NFIA [OR 0.85; P = 2.5 × 10−6]). Neither of these loci is associated with other common, complex autoimmune diseases. Conclusion Anti‐CCP–negative RA and anti‐CCP–positive RA are genetically different disease subsets that only partially share susceptibility factors. Genetic polymorphisms located near the PRL and NFIA genes represent examples of genetic susceptibility

  3. Smoking in combination with antibodies to cyclic citrullinated peptides is associated with persistently high levels of survivin in early rheumatoid arthritis: a prospective cohort study

    PubMed Central

    2014-01-01

    Introduction High levels of the oncoprotein survivin may be detected in the majority of patients with early rheumatoid arthritis (RA). Survivin is a sensitive predictor of joint damage and persistent disease activity. Survivin-positive patients are often poor responders to antirheumatic and biological treatment. The aim of this study was to investigate the reproducibility of survivin status and its significance for clinical and immunological assessment of RA patients. Methods Survivin levels were measured in 339 patients from the Better Anti-Rheumatic FarmacOTherapy (BARFOT) cohort of early RA at baseline and after 24 months. The association of survivin status with joint damage (total Sharp-van der Heijde score), disease activity (Disease Activity Score based on evaluation of 28 joints (DAS28)), functional disability (Health Assessment Questionnaire (HAQ)), and pain perception (Visual Analogue Scale (VAS)) was calculated in the groups positive and negative for survivin on both occasions, and for the positive-negative and negative-positive groups. Results In 268 patients (79%) the levels of survivin were similar at baseline and after 24 months, 15% converted from survivin-positive to survivin-negative, and 5% from survivin-negative to survivin-positive. A combination of smoking and antibodies against cyclic citrullinated peptides (aCCP) predicted persistently (baseline and 24 months) high levels of survivin (odds ratio 4.36 (95% CI: 2.64 to 7.20), P < 0.001), positive predictive value 0.66 and specificity 0.83). The independent nature of survivin and aCCP was demonstrated by statistical and laboratory analysis. Survivin positivity on both test occasions was associated with the progression of joint damage, significantly higher DAS28 and lower rate of remission at 24 and 60 months compared to negative-negative patients. Survivin status was less associated with changes in HAQ and VAS. Conclusions Survivin is a relevant and reproducible marker of severe RA

  4. Rheumatoid factor and antibodies against citrullinated peptides in Moroccan patients with rheumatoid arthritis: association with disease parameters and quality of life.

    PubMed

    Ibn Yacoub, Yousra; Amine, Bouchra; Laatiris, Assia; Hajjaj-Hassouni, Najia

    2012-02-01

    We aimed to evaluate the immunological status and its relationships with disease-related parameters of activity, severity and quality of life in Moroccan patients with rheumatoid arthritis (RA). Two hundred forty-five consecutive patients with RA were recruited. The following data were collected: demographic characteristics, disease duration (years), disease activity (evaluated by the disease activity score, DAS28), structural damage (evaluated by Sharp's method as modified by van der Heijde), functional disability (assessed by using the Moroccan version of the Health Assessment Questionnaire, HAQ) and quality of life (by using the Arabic version of the Medical Outcomes Study Short Form 36 Health Survey: the SF-36). Immunological status (rheumatoid factor rate, RF) and antibodies against citrullinated peptides rate (ACPAs) by the Elisa method were examined. ACPAs were detected in 75.1% of patients with a mean rate of 79.2 ± 43.8 UI. RF was detected in 80.8% of patients with a mean rate of 80.1 ± 50.6 UI. Patients with positive RF and ACPAs had higher disease activity, impaired functional ability, severe structural damage, more ocular symptoms and altered aspects of quality of life. In univariate analysis, higher levels of ACPAs were significantly correlated with the age at onset (r = 0.307), disease duration (r = 0.520), disease activity (DAS28) (r = 0.531), Sharp score (r = 0.431), and with the deterioration of all domains of SF-36 (for all p ≤ 0.01). RF levels were correlated with disease duration (r = 0.517), disease activity (r = 0.470), functional disability (r = 0.521), and the alteration of physical domains of SF-36 (for all p ≤ 0.01). In multivariate analysis, the main factors associated to ACPAs and RF levels were functional disability, structural damage and impaired QoL. Furthermore, using the SF-36 scores as dependent variables, the impairment of physical domains and the domain of vitality were

  5. Antibodies of IgG, IgA and IgM isotypes against cyclic citrullinated peptide precede the development of rheumatoid arthritis

    PubMed Central

    2011-01-01

    Introduction We and others have previously shown that antibodies against cyclic citrullinated proteins (anti-CCP) precede the development of rheumatoid arthritis (RA) and in a more recent study we reported that individuals who subsequently developed RA had increased concentrations of several cytokines and chemokines years before the onset of symptoms of joint disease. Here we aimed to evaluate the prevalence and predictive values of anti-CCP antibodies of IgG, IgM and IgA isotype in individuals who subsequently developed RA and also to relate these to cytokines and chemokines, smoking, genetic factors and radiographic score. Methods A case-control study (1:4 ratio) was nested within the Medical Biobank and the Maternity cohorts of Northern Sweden. Patients with RA were identified from blood donors predating the onset of disease by years. Matched controls were selected randomly from the same registers. IgG, IgA and IgM anti-CCP2 antibodies were determined using EliA anti-CCP assay on ImmunoCAP 250 (Phadia AB, Uppsala, Sweden). Results Of 86 patients with RA identified as blood donors prior to the onset of symptoms, samples were available from 71 for analyses. The median (Q1 to Q3) predating time was 2.5 years (1.1 to 5.9 years). The sensitivity of anti-CCP antibodies in the pre-patient samples was 35.2% for IgG, 23.9% for IgA, and 11.8% for IgM. The presence of IgG and IgA anti-CCP antibodies was highly significant compared with controls. IgG and IgA anti-CCP2 predicted RA significantly in conditional logistic regression models odds ratio (OR) = 94.1, 95% confidence interval (CI) 12.7 to 695.4 and OR = 11.1, 95% CI 4.4 to 28.1, respectively, the IgM anti-CCP showed borderline significance OR = 2.5 95% CI 0.9 to 6.3. Concentrations of all anti-CCP isotypes increased the closer to the onset of symptoms the samples were collected with an earlier and higher increase for IgG and IgA compared with IgM anti-CCP. IgA and IgG anti-CCP positive individuals had different

  6. Development, validation, and comparison of four methods to simultaneously quantify l-arginine, citrulline, and ornithine in human plasma using hydrophilic interaction liquid chromatography and electrospray tandem mass spectrometry.

    PubMed

    Lai, Xianyin; Kline, Jeffrey A; Wang, Mu

    2015-11-15

    To understand the role of l-arginine depletion in impaired nitric oxide synthesis in disease, it is important to simultaneously quantify arginine, citrulline, and ornithine in the plasma. Because the three amino acids are endogenous analytes, true blank matrix for them is not available. It is necessary and valuable to compare the performance of different approaches due to lack of regulatory clarity for validation. A two-step sample preparation method using methanol as protein precipitation reagent was developed in this study is used for sample preparation. Because true blank matrix for endogenous analytes is not available, water as blank matrix, 1% BSA in PBS as blank matrix, surrogate analyte, and background subtraction were designed to establish successful quantification methods. Four methods to simultaneously quantify arginine, citrulline, and ornithine in human plasma using hydrophilic interaction liquid chromatography and electrospray tandem mass spectrometry were developed, validated, and compared. The developed two-step sample preparation method using methanol as protein precipitation reagent in this study needs less time and provides higher recovery comparing with other approaches. Three of the four methods, water as blank matrix, 1% BSA in PBS as blank matrix, and surrogate analyte, have been successful in fulfilling all the criteria, while background subtraction has failed. Results of the measured concentrations in 97 human plasma samples using the three methods show that the difference between any two methods or among the three methods presents 100% of samples with less than 20% for all the three amino acids and majority of them are under 10%. The developed two-step sample preparation method using methanol as protein precipitation reagent is simple and convenient. Three of the four methods are fully validated and the validation is successful. The BSA functioned effectively as a blank matrix for these three amino acids, considering cost, data quality

  7. Influence of human leucocyte antigen‐DRB1 on the susceptibility to rheumatoid arthritis and on the production of anti‐cyclic citrullinated peptide antibodies in a Portuguese population

    PubMed Central

    Ligeiro, D; Fonseca, J E; Abade, O; Abreu, I; Cruz, M; Nero, P; Cavaleiro, J; Teles, J; Trindade, H; Caetano, J M; Branco, J

    2007-01-01

    Objective To clarify the influence of the HLA‐DRB1 locus on the susceptibility to rheumatoid arthritis and the production of anti‐cyclic citrullinated peptide antibodies (anti‐CCP) in a Portuguese population. Methods: 141 patients with rheumatoid arthritis fulfilling the American College of Rheumatology 1987 revised criteria for rheumatoid arthritis were compared with 150 healthy controls. Human leucocyte antigen (HLA)‐DRB1 locus genotyping was assessed by polymerase chain reaction reverse probing assays and sequence‐specific primers. Anti‐CCP antibodies were quantified by ELISA in patients with rheumatoid arthritis. Frequencies between groups were compared by the two‐sided Fisher's exact test and considered significant if p<0.05. Results The HLA‐DRB1*04 and HLA‐DRB1*10 groups were highly associated with rheumatoid arthritis (p<0.001 and p = 0.031, respectively). High titres of anti‐CCP antibodies were largely associated with the presence of HLA‐DRB1*04/10. Conclusion The well‐recognised susceptibility alleles to rheumatoid arthritis, HLA‐DRB1*04, were associated with rheumatoid arthritis in Portuguese patients. The relatively rare DRB1*10 was also associated with rheumatoid arthritis, as was described previously in other southern European countries. Both groups were associated with high anti‐CCP titres, reinforcing its relevance to disease onset. PMID:16793843

  8. Longitudinal analysis of citrullinated protein/peptide antibodies (anti-CP) during 5 year follow up in early rheumatoid arthritis: anti-CP status predicts worse disease activity and greater radiological progression

    PubMed Central

    Ronnelid, J; Wick, M; Lampa, J; Lindblad, S; Nordmark, B; Klareskog, L; van Vollenhoven, R F

    2005-01-01

    Objective: To study serum levels of citrullinated protein/peptide antibodies (anti-CP) during up to 5 years' follow up of patients with early rheumatoid arthritis (RA), and to relate serum levels to disease course and to treatments in clinical practice. Methods: 279 patients with early RA were followed up with clinical investigations, radiographs, and measurement of anti-CP at baseline and after 3 months, 1, 2, 3, and 5 years. Results: 160/279 (57.3%) patients were anti-CP positive at the first visit (mean 5 months after first symptoms). During follow up only 11/279 (3.9%) of the patients changed their anti-CP status. Anti-CP levels fell significantly during the first year, and this drop correlated with the extent of sulfasalazine treatment but not with other drugs or clinical indices. Anti-CP positive and negative patients had similar disease activities at baseline, but during follow up the anti-CP positive patients had worse clinical disease and greater radiological progression, despite at least equally intensive antirheumatic treatment. Conclusions: Anti-CP are stable during the first 5 years of RA, suggesting that events before rather than after onset of clinical manifestations of disease determine this phenotype. The presence of anti-CP at diagnosis predicts a less favourable disease course and greater radiological progression despite antirheumatic treatment, but subsequent changes in antibody levels do not reflect changes in disease activity. Taken together, these observations suggest that anti-CP positive RA is a distinct clinical and pathophysiological entity. PMID:15843452

  9. Data in the activities of caspases and the levels of reactive oxygen species and cytochrome c in the •OH-induced fish erythrocytes treated with alanine, citrulline, proline and their combination

    PubMed Central

    Li, Huatao; Jiang, Weidan; Liu, Yang; Jiang, Jun; Zhang, Yongan; Wu, Pei; Zhao, Juan; Duan, Xudong; Zhou, Xiaoqiu; Feng, Lin

    2016-01-01

    The present study explored the effects of alanine (Ala), citrulline (Cit), proline (Pro) and their combination (Ala10Pro4Cit1) on the activities of caspases and levels of reactive oxygen species (ROS) and cytochrome c in hydroxyl radicals (•OH)-induced carp erythrocytes. The data displayed that •OH induced the increases in the activities of caspase−3, caspase−8 and caspase−9 and the levels of ROS and cytochrome c in carp erythrocytes. However, Ala, Cit, Pro and Ala10Pro4Cit1 effectively suppressed the •OH-induced increases in the activities of caspase−3, caspase−8 and caspase−9 and the levels of ROS and cytochrome c in carp erythrocytes. Furthermore, the activities of caspase−3, caspase−8 and caspase−9 and the levels of ROS and cytochrome c were gradually decreased with increasing concentrations of Ala, Cit, Pro and Ala10Pro4Cit1 (0.175−1.400 mM) in the •OH-induced carp erythrocytes. These data demonstrated that the 50% inhibitory doses (ID50) of Ala10Pro4Cit1 on the activities of caspase−8, caspase−9 and caspase−3 and levels of ROS and cytochrome c were respectively estimated to be the minimum values among amino acids examined so far. The 5% inhibitory doses (ID5) of Ala, Cit, Pro and Ala10Pro4Cit1 on the activities of caspase−8, caspase−9 and caspase−3 and levels of ROS and cytochrome c were estimated to be at their physiological concentrations in mammalian. Our research article for further interpretation and discussion from these data in Li et al. (2016) [1]. PMID:26952131

  10. Data in the activities of caspases and the levels of reactive oxygen species and cytochrome c in the •OH-induced fish erythrocytes treated with alanine, citrulline, proline and their combination.

    PubMed

    Li, Huatao; Jiang, Weidan; Liu, Yang; Jiang, Jun; Zhang, Yongan; Wu, Pei; Zhao, Juan; Duan, Xudong; Zhou, Xiaoqiu; Feng, Lin

    2016-06-01

    The present study explored the effects of alanine (Ala), citrulline (Cit), proline (Pro) and their combination (Ala10Pro4Cit1) on the activities of caspases and levels of reactive oxygen species (ROS) and cytochrome c in hydroxyl radicals (•OH)-induced carp erythrocytes. The data displayed that •OH induced the increases in the activities of caspase-3, caspase-8 and caspase-9 and the levels of ROS and cytochrome c in carp erythrocytes. However, Ala, Cit, Pro and Ala10Pro4Cit1 effectively suppressed the •OH-induced increases in the activities of caspase-3, caspase-8 and caspase-9 and the levels of ROS and cytochrome c in carp erythrocytes. Furthermore, the activities of caspase-3, caspase-8 and caspase-9 and the levels of ROS and cytochrome c were gradually decreased with increasing concentrations of Ala, Cit, Pro and Ala10Pro4Cit1 (0.175-1.400 mM) in the •OH-induced carp erythrocytes. These data demonstrated that the 50% inhibitory doses (ID50) of Ala10Pro4Cit1 on the activities of caspase-8, caspase-9 and caspase-3 and levels of ROS and cytochrome c were respectively estimated to be the minimum values among amino acids examined so far. The 5% inhibitory doses (ID5) of Ala, Cit, Pro and Ala10Pro4Cit1 on the activities of caspase-8, caspase-9 and caspase-3 and levels of ROS and cytochrome c were estimated to be at their physiological concentrations in mammalian. Our research article for further interpretation and discussion from these data in Li et al. (2016) [1]. PMID:26952131

  11. [Diagnostic difficulties in polymyositis].

    PubMed

    Majewski, Dominik; Puszczewicz, Mariusz; Tuchocka-Piotrowska, Aleksandra; Kołczewska, Aleksandra

    2006-01-01

    Polymyositis is a connective tissue disease. Although myositis is the dominant clinical manifestation, internal organs may also be affected. Arthritis occurs in 30% of patients, especially in the course of the anti-synthetase syndrome. We report on a case of a woman with polymyositis and interstitial lung disease. Arthritis and the presence of anti-cyclic citrullinated peptide antibodies in the patient's serum may suggest the diagnosis of the overlap syndrome. PMID:17474177

  12. Smoking interacts with HLA-DRB1 shared epitope in the development of anti-citrullinated protein antibody-positive rheumatoid arthritis: results from the Malaysian Epidemiological Investigation of Rheumatoid Arthritis (MyEIRA)

    PubMed Central

    2012-01-01

    Introduction Rheumatoid arthritis (RA) is a multifactorial autoimmune disease in which genetic and environmental factors interact in the etiology. In this study, we investigated whether smoking and HLA-DRB1 shared-epitope (SE) alleles interact differently in the development of the two major subgroups of rheumatoid arthritis (RA), anti-citrullinated proteins antibody (ACPA)-positive and ACPA-negative disease, in a multiethnic population of Asian descent. Methods A case-control study comprising early diagnosed RA cases was carried out in Malaysia between 2005 and 2009. In total, 1,076 cases and 1,612 matched controls participated in the study. High-resolution HLA-DRB1 genotyping was performed for shared-epitope (SE) alleles. All participants answered a questionnaire on a broad range of issues, including smoking habits. The odds ratio (OR) of developing ACPA-positive and ACPA-negative disease was calculated for smoking and the presence of any SE alleles separately. Potential interaction between smoking history (defined as "ever" and "never" smoking) and HLA-DRB1 SE alleles also was calculated. Results In our multiethnic study, both the SE alleles and smoking were associated with an increased risk of developing ACPA-positive RA (OR SE alleles, 4.7; 95% confidence interval (CI), 3.6 to 6.2; OR smoking, 4.1; 95% CI, 1.9 to 9.2). SE-positive smokers had an odds ratio of ACPA-positive RA of 25.6 (95% CI, 10.4 to 63.4), compared with SE-negative never-smokers. The interaction between smoking and SE alleles was significant (attributable proportion due to interaction (AP) was 0.7 (95% CI, 0.5 to 1.0)). The HLA-DRB1*04:05 SE allele, which is common in Asian populations, but not among Caucasians, was associated with an increased risk of ACPA-positive RA, and this allele also showed signs of interaction with smoking (AP, 0.4; 95% CI, -0.1 to 0.9). Neither smoking nor SE alleles nor their combination was associated with an increased risk of ACPA-negative RA. Conclusions The risk

  13. Association of Valine and Leucine at HLA–DRB1 Position 11 With Radiographic Progression in Rheumatoid Arthritis, Independent of the Shared Epitope Alleles but Not Independent of Anti–Citrullinated Protein Antibodies

    PubMed Central

    van Steenbergen, H. W.; Raychaudhuri, S.; Rodríguez-Rodríguez, L.; Rantapää-Dahlqvist, S.; Berglin, E.; Toes, R. E. M.; Huizinga, T. W. J.; Fernández-Gutiérrez, B.; Gregersen, P. K.; van der Helm-van Mil, A. H. M.

    2015-01-01

    Objective For decades it has been known that the HLA–DRB1 shared epitope (SE) alleles are associated with an increased risk of development and progression of rheumatoid arthritis (RA). Recently, the following variations in the peptide-binding grooves of HLA molecules that predispose to RA development have been identified: Val and Leu at HLA–DRB1 position 11, Asp at HLA–B position 9, and Phe at HLA–DPB1 position 9. This study was undertaken to investigate whether these variants are also associated with radiographic progression in RA, independent of SE and anti–citrullinated protein antibody (ACPA) status. Methods A total of 4,911 radiograph sets from 1,878 RA patients included in the Leiden Early Arthritis Clinic (The Netherlands), Umeå (Sweden), Hospital Clinico San Carlos–Rheumatoid Arthritis (Spain), and National Data Bank for Rheumatic Diseases (US) cohorts were studied. HLA was imputed using single-nucleotide polymorphism data from an Immunochip, and the amino acids listed above were tested in relation to radiographic progression per cohort using an additive model. Results from the 4 cohorts were combined in inverse-variance weighted meta-analyses using a fixed-effects model. Analyses were conditioned on SE and ACPA status. Results Val and Leu at HLA–DRB1 position 11 were associated with more radiographic progression (meta-analysis P = 5.11 × 10−7); this effect was independent of SE status (meta-analysis P = 0.022) but not independent of ACPA status. Phe at HLA–DPB1 position 9 was associated with more severe radiographic progression (meta-analysis P = 0.024), though not independent of SE status. Asp at HLA–B position 9 was not associated with radiographic progression. Conclusion Val and Leu at HLA–DRB1 position 11 conferred a risk of a higher rate of radiographic progression independent of SE status but not independent of ACPA status. These findings support the relevance of these amino acids at position 11. PMID:25580908

  14. [Early rheumatoid arthritis].

    PubMed

    Babić-Naglić, Durdica

    2008-01-01

    Rheumatoid arthritis (RA) is chronic joint disease which if untreated leads to permanent structural damage and disability. Early diagnosis and therapy are the main requests for good clinical practice. Early diagnosis tools include specific clinical assesment, serological, immunogenetic and radiological evaluation. Disease activity score is cornerstone in clinical assesment, rheumatoid factor and anti-cyclic citrullinated peptide antibodies (anti-CCP) are very specific serological parameters. The shared epitope containing HLA-DRB1* alleles represent the most significant genetic risk for RA. Magnetic resonance and ultrasound imaging are very sensitive methods in early phase of disease. PMID:19024271

  15. Diagnosis and classification of rheumatoid arthritis.

    PubMed

    Kourilovitch, Maria; Galarza-Maldonado, Claudio; Ortiz-Prado, Esteban

    2014-01-01

    Rheumatoid arthritis (RA) is a systemic chronic inflammatory disease of unclear etiology that is manifested in by a progressive and destructive polyarthritis in association with serological evidence of autoreactivity. Its diagnosis is based on the classification criteria that involve four parameters: joint involvement, serology (rheumatoid factor and anti-cyclic citrullinated peptide--anti-CCP), levels of acute phase reactants and the duration of the symptoms Aletaha, et al. [1]. This classification simplifies the categorization of the patients with early RA; however, the diagnosis requires highly trained specialists who are able to differentiate early symptoms of RA from other pathologies. PMID:24568777

  16. Serum Levels of Anticyclic Citrullinated Peptide Antibodies, Interleukin-6, Tumor Necrosis Factor-α, and C-Reactive Protein Are Associated with Increased Carotid Intima-Media Thickness: A Cross-Sectional Analysis of a Cohort of Rheumatoid Arthritis Patients without Cardiovascular Risk Factors

    PubMed Central

    Vázquez-Del Mercado, Mónica; Nuñez-Atahualpa, Lourdes; Figueroa-Sánchez, Mauricio; Gómez-Bañuelos, Eduardo; Rocha-Muñoz, Alberto Daniel; Martín-Márquez, Beatriz Teresita; Martínez-García, Erika Aurora; Macias-Reyes, Héctor; Gamez-Nava, Jorge Ivan; Navarro-Hernandez, Rosa Elena; Nuñez-Atahualpa, María Alejandra; Andrade-Garduño, Javier

    2015-01-01

    The main cause of death in rheumatoid arthritis (RA) is cardiovascular events. We evaluated the relationship of anticyclic citrullinated peptide (anti-CCP) antibody levels with increased carotid intima-media thickness (cIMT) in RA patients. Methods. Forty-five anti-CCP positive and 37 anti-CCP negative RA patients, and 62 healthy controls (HC) were studied. All groups were assessed for atherogenic index of plasma (AIP) and cIMT. Anti-CCP, C-reactive protein (CRP), and levels of tumor necrosis factor alpha (TNFα) and interleukin-6 (IL-6) were measured by enzyme-linked immunosorbent assay (ELISA). Results. The anti-CCP positive RA patients showed increased cIMT compared to HC and anti-CCP negative (P < 0.001). Anti-CCP positive versus anti-CCP negative RA patients, had increased AIP, TNFα and IL-6 (P < 0.01), and lower levels of high density lipoprotein cholesterol (HDL-c) (P = 0.02). The cIMT correlated with levels of anti-CCP (r = 0.513, P = 0.001), CRP (r = 0.799, P < 0.001), TNFα (r = 0.642, P = 0.001), and IL-6 (r = 0.751, P < 0.001). In multiple regression analysis, cIMT was associated with CRP (P < 0.001) and anti-CCP levels (P = 0.03). Conclusions. Levels of anti-CCP and CRP are associated with increased cIMT and cardiovascular risk supporting a clinical role of the measurement of cIMT in RA in predicting and preventing cardiovascular events. PMID:25821796

  17. No evidence of major effects in several Toll-like receptor gene polymorphisms in rheumatoid arthritis

    PubMed Central

    Jaen, Olivier; Petit-Teixeira, Elisabeth; Kirsten, Holger; Ahnert, Peter; Semerano, Luca; Pierlot, Céline; Cornelis, Francois; Boissier, Marie-Christophe; Falgarone, Geraldine

    2009-01-01

    Introduction The objective was to study the potential genetic contribution of Toll-like receptor (TLR) genes in rheumatoid arthritis (RA). TLRs bind to pathogen-associated molecular patterns, and TLR genes influence both proinflammatory cytokine production and autoimmune responses. Host–pathogen interactions are involved in RA physiopathology. Methods We tested SNPs of five TLR genes (TLR9, TLR2, TLR6, TLR1, and TLR4) in a cohort of 100 French families with RA. Genotypes were analyzed using the transmission disequilibrium test. As TLR2, TLR6, and TLR1 are located on chromosome 4, we determined the haplotype relative risk. Analyses were performed in subgroups defined by status for rheumatoid factor, anti-cyclic citrullinated peptide autoantibodies, and erosions. Results We found no disequilibrium in allele transmission for any of the SNPs of the five TLR genes. In subgroup analyses, no associations were detected linking TLR9, TLR2, or TLR9/TLR2 to rheumatoid factor, anti-cyclic citrullinated peptide autoantibodies, or erosions. Haplotype analysis of the polymorphisms showed no haplotype associations in any of the subgroups. Conclusions We found no evidence of major effects of TLR gene polymorphisms in RA, although we tested different TLR phenotypes. Moreover, no associations were noted with autoantibody production or erosions. PMID:19134200

  18. Protein Arginine Methylation and Citrullination in Epigenetic Regulation

    PubMed Central

    2015-01-01

    The post-translational modification of arginine residues represents a key mechanism for the epigenetic control of gene expression. Aberrant levels of histone arginine modifications have been linked to the development of several diseases including cancer. In recent years, great progress has been made in understanding the physiological role of individual arginine modifications and their effects on chromatin function. The present review aims to summarize the structural and functional aspects of histone arginine modifying enzymes and their impact on gene transcription. We will discuss the potential for targeting these proteins with small molecules in a variety of disease states. PMID:26686581

  19. Protein Arginine Methylation and Citrullination in Epigenetic Regulation.

    PubMed

    Fuhrmann, Jakob; Thompson, Paul R

    2016-03-18

    The post-translational modification of arginine residues represents a key mechanism for the epigenetic control of gene expression. Aberrant levels of histone arginine modifications have been linked to the development of several diseases including cancer. In recent years, great progress has been made in understanding the physiological role of individual arginine modifications and their effects on chromatin function. The present review aims to summarize the structural and functional aspects of histone arginine modifying enzymes and their impact on gene transcription. We will discuss the potential for targeting these proteins with small molecules in a variety of disease states. PMID:26686581

  20. Arginine, citrulline and nitric oxide metabolism in sepsis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arginine has vasodilatory effects, via its conversion by nitric oxide (NO) synthase into NO, and immunomodulatory actions that play important roles in sepsis. Protein breakdown affects arginine availability, and the release of asymmetric dimethylarginine, an inhibitor of NO synthase, may therefore a...

  1. L-citrulline levels in watermelon cultivars from three locations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Producers of fresh fruit and vegetables face increasing production costs and more intense international market competition. Maximizing marketability by offering high quality produce that is also highly nutritious gives new market niches for some crops, such as watermelons, if appropriate germplasm ...

  2. Interaction between extracellular matrix molecules and microbial pathogens: evidence for the missing link in autoimmunity with rheumatoid arthritis as a disease model

    PubMed Central

    Sofat, Nidhi; Wait, Robin; Robertson, Saralili D.; Baines, Deborah L.; Baker, Emma H.

    2015-01-01

    Rheumatoid arthritis (RA) is an autoimmune disease characterized by inflammation followed by tissue rebuilding or fibrosis. A failure by the body to regulate inflammation effectively is one of the hallmarks of RA. The interaction between the external environment and the human host plays an important role in the development of autoimmunity. In RA, the observation of anti-cyclic citrullinated peptide antibodies (ACPA) to autoantigens is well recognized. Citrullination is a post-translational modification mediated by peptidyl arginine deiminases, which exist in both mammalian and bacterial forms. Previous studies have shown how proteins expressed in the human extracellular matrix (ECM) acquire properties of damage-associated molecular patterns (DAMPs) in RA and include collagens, tenascin-C, and fibronectin (FN). ECM DAMPs can further potentiate tissue damage in RA. Recent work has shown that citrullination in RA occurs at mucosal sites, including the oral cavity and lung. Mucosal sites have been linked with bacterial infection, e.g., periodontal disease, where exogenous pathogens are implicated in the development of autoimmunity via an infectious trigger. Proteases produced at mucosal sites, both by bacteria and the human host, can induce the release of ECM DAMPs, thereby revealing neoepitopes which can be citrullinated and lead to an autoantibody response with further production of ACPA. In this perspectives article, the evidence for the interplay between the ECM and bacteria at human mucosal surfaces, which can become a focus for citrullination and the development of autoimmunity, is explored. Specific examples, with reference to collagen, fibrinogen, and FN, are discussed. PMID:25642219

  3. Identification of novel antiacetylated vimentin antibodies in patients with early inflammatory arthritis

    PubMed Central

    Juarez, Maria; Bang, Holger; Hammar, Friederike; Reimer, Ulf; Dyke, Bernard; Sahbudin, Ilfita; Buckley, Christopher D; Fisher, Benjamin; Filer, Andrew; Raza, Karim

    2016-01-01

    Objective To investigate serum antibody reactivity against a panel of post-translationally modified vimentin peptides (PTMPs) in patients with early inflammatory arthritis. Methods A panel of PTMPs was developed. Microtitre plates were coated with peptides derived from vimentin that were identical in length and composition except at one amino acid that was changed to introduce one of three post-translational modifications (PTMs)—either a citrullinated, carbamylated or acetylated residue. Sera of 268 treatment-naive patients with early inflammatory arthritis and symptoms ≤3 months' duration were tested. Patients were assigned to one of three outcome categories at 18-month follow-up (rheumatoid arthritis (RA), persistent non-RA arthritis and resolving arthritis). Results Antibodies against citrullinated, carbamylated and acetylated vimentin peptides were detected in the sera of patients with early inflammatory arthritis. The proportion of patients seropositive for all antibody types was significantly higher in the RA group than in the other groups. Anti cyclic citrullinated peptide (CCP)-positive patients with RA had higher numbers of peptides recognised and higher levels of antibodies against those peptides, representing a distinct profile compared with the other groups. Conclusions We show for the first time that antibodies against acetylated vimentin are present in the sera of patients with early RA and confirm and extend previous observations regarding anticitrullinated and anticarbamylated antibodies. PMID:26160441

  4. PADI4 Haplotypes in Association with RA Mexican Patients, a New Prospect for Antigen Modulation

    PubMed Central

    Gonzalez-Montoya, Norma Guadalupe; Gamez-Nava, Jorge I.; Moran-Moguel, Maria Cristina; Rosales-Gomez, Roberto Carlos; Gutierrez-Rubio, Susan Andrea; Sanchez-Corona, Jose; Davalos-Rodriguez, Ingrid Patricia; Salazar-Paramo, Mario

    2013-01-01

    Peptidyl arginine deiminase IV (PAD 4) is the responsible enzyme for a posttranslational modification called citrullination, originating the antigenic determinant recognized by anti-cyclic citrullinated peptide antibodies (ACPA). Four SNPs (single nucleotide polymorphisms) have been described in PADI4 gene to form a susceptibility haplotype for rheumatoid arthritis (RA); nevertheless, results in association studies appear contradictory in different populations. The aim of the study was to analyze if the presence of three SNPs in PADI4 gene susceptibility haplotype (GTG) is associated with ACPA positivity in patients with RA. This was a cross-sectional study that included 86 RA patients and 98 healthy controls. Polymorphisms PADI4_89, PADI4_90, and PADI4_92 in the PADI4 gene were genotyped. The susceptibility haplotype (GTG) was more frequent in RA patients; interestingly, we found a new haplotype associated with RA with a higher frequency (GTC). There were no associations between polymorphisms and high scores in Spanish HAQ-DI and DAS-28, but we did find an association between RARBIS index and PADI4_89, PADI4_90 polymorphisms. We could not confirm an association between susceptibility haplotype presence and ACPA positivity. Further evidence about proteomic expression of this gene will determine its participation in antigenic generation and autoimmunity. PMID:24454473

  5. PADI4 haplotypes in association with RA Mexican patients, a new prospect for antigen modulation.

    PubMed

    Zavala-Cerna, Maria Guadalupe; Gonzalez-Montoya, Norma Guadalupe; Nava, Arnulfo; Gamez-Nava, Jorge I; Moran-Moguel, Maria Cristina; Rosales-Gomez, Roberto Carlos; Gutierrez-Rubio, Susan Andrea; Sanchez-Corona, Jose; Gonzalez-Lopez, Laura; Davalos-Rodriguez, Ingrid Patricia; Salazar-Paramo, Mario

    2013-01-01

    Peptidyl arginine deiminase IV (PAD 4) is the responsible enzyme for a posttranslational modification called citrullination, originating the antigenic determinant recognized by anti-cyclic citrullinated peptide antibodies (ACPA). Four SNPs (single nucleotide polymorphisms) have been described in PADI4 gene to form a susceptibility haplotype for rheumatoid arthritis (RA); nevertheless, results in association studies appear contradictory in different populations. The aim of the study was to analyze if the presence of three SNPs in PADI4 gene susceptibility haplotype (GTG) is associated with ACPA positivity in patients with RA. This was a cross-sectional study that included 86 RA patients and 98 healthy controls. Polymorphisms PADI4_89, PADI4_90, and PADI4_92 in the PADI4 gene were genotyped. The susceptibility haplotype (GTG) was more frequent in RA patients; interestingly, we found a new haplotype associated with RA with a higher frequency (GTC). There were no associations between polymorphisms and high scores in Spanish HAQ-DI and DAS-28, but we did find an association between RARBIS index and PADI4_89, PADI4_90 polymorphisms. We could not confirm an association between susceptibility haplotype presence and ACPA positivity. Further evidence about proteomic expression of this gene will determine its participation in antigenic generation and autoimmunity. PMID:24454473

  6. Diagnostic performance of a new vimentin-derived ACPA (CCP high sensitive) in patients with rheumatoid arthritis.

    PubMed

    Bertin, Daniel; Dubucquoi, Sylvain; Lakomy, Daniela; Deleplancque, Anne-Sophie; Desplat-Jégo, Sophie

    2016-04-01

    Autoantibodies are a common feature of rheumatoid arthritis (RA), and their detection is used as a diagnostic tool in medical practice. Rheumatoid factor (RF) and/or anti-citrullinated protein antibodies (ACPA) detection in patients' sera are now included in 2010 ACR/EULAR criteria for RA diagnosis. In this study, we evaluated a new vimentin-derived ACPA ELISA, the anti-cyclic citrullinated peptide high sensitive (CCP hs) test, and we compared its performance with the RF IgM and anti-CCP3 tests on a French multicenter cohort of 84 RA patients, 107 non-RA patients and 100 healthy controls. Sensitivities for RA diagnosis were 71.4, 84.5 and 64.3 % and specificities were 88.4, 86.9 and 87.3 % for CCP hs, CCP3 and RF IgM, respectively. There was a moderate correlation between CCP hs and CCP3 titers (Pearson's r = 0.43; p < 0.0001). These results support the contention that anti-CCP hs antibodies are new reliable ACPA with high specificity for RA. PMID:26350265

  7. Dietary arginine requirements for growth are dependent on the rate of citrulline production in mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In many species, including humans, arginine is considered a semiessential amino acid because under certain conditions endogenous synthesis cannot meet its demand. The requirements of arginine for growth in mice are ill defined and seem to vary depending on the genetic background of the mice. The obj...

  8. Structure of a Novel N-acetyl-L-citrulline Deacetylase from Xanthomonas campestris

    SciTech Connect

    Shi,D.; Yu, X.; Roth, L.; Tuchman, M.; Allewell, N.

    2007-01-01

    The structure of a novel acetylcitrulline deacetylase from the plant pathogen Xanthomonas campestris has been solved by multiple-wavelength anomalous dispersion (MAD) using crystals grown from selenomethionine-substituted protein and refined at 1.75 {angstrom} resolution. The asymmetric unit of the crystal contains one monomer consisting of two domains, a catalytic domain and a dimerization domain. The catalytic domain is able to bind a single Co(II) ion at the active site with no change in confirmation. the dimerization domain forms an interface between two monomers related by a crystallographic two-fold symmetry axis. The interface is maintained by hydrophobic interactions between helices and hydrogen bonding between two {beta} strands that form a continuous {beta} sheet across the dimer interface. Because the dimers are also related by two-fold crystallographic axes, they pack together across the crystal via the dimerization domain, suggesting that higher order oligomers may form in solution. The polypeptide fold of the monomer is similar to the fold of Pseudomonas sp. carboxypeptidase G2 and Neisseria meningitidis succinyl diaminopimelate desuccinylase. Structural comparison among these enzymes allowed modeling of substrate binding and suggests a possible catalytic mechanism, in which Glu130 functions as a bifunctional general acid-base catalyst and the metal ion polarizes the carbonyl of the acetyl group.

  9. Citrulline synthesis in rat tissues and liver content of carbamoyl phosphate and ornithine

    PubMed Central

    Raijman, Luisa

    1974-01-01

    Rat liver ornithine carbamoyltransferase appears to be located exclusively in the mitochondria; the activity that is found in the soluble fraction is indistinguishable from mitochondrial ornithine carbamoyltransferase by simple kinetic criteria, and seems to result from breakage of mitochondria during homogenization. Of several rat tissues studied, only the liver and the mucosa of small intestine contain significant amounts of ornithine carbamoyltransferase; the activity in intestinal mucosa is less than one thousandth of that in liver. Qualitatively, this distribution coincides with that of carbamoyl phosphate synthetase I and its cofactor, acetylglutamate. The rat liver contents of carbamoyl phosphate and ornithine were 0.1 and 0.15μmol/g wet wt. of tissue respectively. On the basis of these values, it is proposed that in vivo the ornithine carbamoyltransferase activity of liver may be much lower than its maximal activity in vitro might suggest. PMID:4822731

  10. Peptides Presented by HLA-DR Molecules in Synovia of Patients with Rheumatoid Arthritis or Antibiotic-Refractory Lyme Arthritis*

    PubMed Central

    Seward, Robert J.; Drouin, Elise E.; Steere, Allen C.; Costello, Catherine E.

    2011-01-01

    Disease-associated HLA-DR molecules, which may present autoantigens, constitute the greatest genetic risk factor for rheumatoid arthritis (RA) and antibiotic-refractory Lyme arthritis (LA). The peptides presented by HLA-DR molecules in synovia have not previously been defined. Using tandem mass spectrometry, rigorous database searches, and manual spectral interpretation, we identified 1,427 HLA-DR-presented peptides (220–464 per patient) from the synovia of four patients, two diagnosed with RA and two diagnosed with LA. The peptides were derived from 166 source proteins, including a wide range of intracellular and plasma proteins. A few epitopes were found only in RA or LA patients. However, two patients with different diseases who had the same HLA allele had the largest number of epitopes in common. In one RA patient, peptides were identified as originating from source proteins that have been reported to undergo citrullination under other circumstances, yet neither this post-translational modification nor anti-cyclic citrullinated peptide antibodies were detected. Instead, peptides with the post-translational modification of S-cysteinylation were identified. We conclude that a wide range of proteins enter the HLA-DR pathway of antigen-presenting cells in the patients' synovial tissue, and their HLA-DR genotype, not the disease type, appears to be the primary determinant of their HLA-DR-peptide repertoire. New insights into the naturally presented HLA-DR epitope repertoire in target tissues may allow the identification of pathogenic T cell epitopes, and this could lead to innovative therapeutic interventions. PMID:21081667

  11. Blockade of tumour necrosis factor α significantly alters the serum level of IgG- and IgA-rheumatoid factor in patients with rheumatoid arthritis

    PubMed Central

    Yazdani-Biuki, B; Stadlmaier, E; Mulabecirovic, A; Brezinschek, R; Tilz, G; Demel, U; Mueller, T; Brickmann, K; Graninger, W; Brezinschek, H

    2005-01-01

    Methods: 12 consecutive patients with seropositive RA treated with etanercept were studied and followed up for 9 months. Clinical efficacy of treatment was evaluated using the 28 joint count Disease Activity Score (DAS28). Serum samples were collected at baseline and after 9 months and serum immunoglobulin, RF isotypes, and anti-cyclic citrullinated peptide (aCCP), antinuclear, nucleosome, and dsDNA antibodies determined. For comparison 7 patients with seropositive RA treated with adalimumab were studied. Results: DAS28 decreased significantly after the first month and then was constant for the whole study (5.7 (0.3) v 3.8 (0.2), p⩽0.000). Serum IgA-RF and IgG-RF increased significantly after 9 months' etanercept treatment (mean (SEM) IgA-RF rose from 19.5 (4.8) to 30.5 (5.9) IU/ml, p⩽0.01; IgG-RF from 20.6 (8.1) to 33.8 (11.5) IU/ml, p⩽0.04). Serum levels of total immunoglobulin and specific autoantibodies remained unchanged during the study. In patients treated with adalimumab, no significant changes in serum levels of RF isotypes and aCCP antibodies were seen. Conclusion: Etanercept, although effective in treating the clinical symptoms of RA, seems to have a pivotal effect on RF-producing B cells either directly or indirectly. PMID:16014683

  12. Predictive Value of Autoantibody Testing for Validating Self-reported Diagnoses of Rheumatoid Arthritis in the Women's Health Initiative

    PubMed Central

    Walitt, Brian; Mackey, Rachel; Kuller, Lewis; Deane, Kevin D.; Robinson, William; Holers, V. Michael; Chang, Yue-Fang; Moreland, Larry

    2013-01-01

    Rheumatoid arthritis (RA) research using large databases is limited by insufficient case validity. Of 161,808 postmenopausal women in the Women's Health Initiative, 15,691 (10.2%) reported having RA, far higher than the expected 1% population prevalence. Since chart review for confirmation of an RA diagnosis is impractical in large cohort studies, the current study (2009–2011) tested the ability of baseline serum measurements of rheumatoid factor and anti-cyclic citrullinated peptide antibodies, second-generation assay (anti-CCP2), to identify physician-validated RA among the chart-review study participants with self-reported RA (n = 286). Anti-CCP2 positivity had the highest positive predictive value (PPV) (80.0%), and rheumatoid factor positivity the lowest (44.6%). Together, use of disease-modifying antirheumatic drugs and anti-CCP2 positivity increased PPV to 100% but excluded all seronegative cases (approximately 15% of all RA cases). Case definitions inclusive of seronegative cases had PPVs between 59.6% and 63.6%. False-negative results were minimized in these test definitions, as evidenced by negative predictive values of approximately 90%. Serological measurements, particularly measurement of anti-CCP2, improved the test characteristics of RA case definitions in the Women's Health Initiative. PMID:23492764

  13. Long-term clinical course of idiopathic pulmonary haemosiderosis with rheumatoid arthritis.

    PubMed

    Sugimoto, Shunsuke; Terada, Jiro; Naito, Akira; Nishimura, Rintaro; Tsushima, Kenji; Tatsumi, Koichiro

    2016-09-01

    Idiopathic pulmonary haemosiderosis (IPH) is a rare cause of diffuse alveolar haemorrhage during childhood, and its precise pathophysiology and long-term clinical course remain unclear. A 31-year-old man was diagnosed with IPH at four years of age and had recurrent episodes of haemoptysis. The patient's symptoms responded well to steroids. However, pulmonary fibrosis and the cystic region in the lung progressively worsened. At age 27, the patient developed polyarthritis with positive anti-cyclic citrullinated peptide antibodies. The patient also developed hand synovitis, which was diagnosed with ultrasonography. These results indicate complications from rheumatoid arthritis. The patient's dyspnoea gradually worsened, and at the age of 31, he developed pneumothorax and an acute exacerbation of IPH. The clinical course from ages 4 to 31 included progressive chronic respiratory failure because of pulmonary fibrosis, acute exacerbations, complications with rheumatoid arthritis, and deliberation regarding lung transplantation. The development of rheumatoid arthritis after the onset of IPH supports the theory of an autoimmune mechanism of IPH. PMID:27516890

  14. The Effect of SHH-Gli Signaling Pathway on the Synovial Fibroblast Proliferation in Rheumatoid Arthritis.

    PubMed

    Qin, Suping; Sun, Dexu; Li, Hui; Li, Xiangyang; Pan, Wei; Yan, Chao; Tang, Renxian; Liu, Xiaomei

    2016-04-01

    Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by chronic synovitis. This study aims to investigate the role of sonic hedgehog (SHH)-Gli signaling pathway in synovial fibroblast proliferation in rheumatoid arthritis. The expression of serum SHH in RA patients group was significantly increased compared with the systemic lupus erythematosus (SLE), ankylosing spondylitis (AS), and healthy subject (healthy control, HC) groups, respectively; serum SHH expression of RA patients was positively correlated with rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibodies (anti-CCP Ab), while there was no significant correlation between SHH expression and erythrocyte sedimentation rate (ESR). SHH, Ptch, Smo, and Gli molecules were highly expressed in rat RA-synovial fibroblast (RA-SF); after blocking the SHH-Gli signaling pathway with a Gli specific inhibitor, Gli-antagonist 61 (GANT61), RA-SF proliferation was inhibited in a dose-dependent manner and the apoptosis rate of RA-SF was increased as well; the expression levels of fibroblast growth factor receptor 1 (FGFR1) and FGFR3 declined in SF cells after GANT61 treatment. Our results suggest that SHH-Gli pathway is involved in the pathogenesis of RA, and blocking SHH-Gli pathway inhibits RA-SF cell proliferation and increases cell apoptosis, which may shed light on developing new ideas for RA treatment. PMID:26552406

  15. GITRL is associated with increased autoantibody production in patients with rheumatoid arthritis.

    PubMed

    Li, Linbo; Wen, Wen; Jia, Rulin; Li, Yuhui; Liu, Xu; Sun, Xiaolin; Li, Zhanguo

    2016-09-01

    The study aimed to determine the serum level of glucocorticoid-induced tumor necrosis factor receptor family-related protein ligand (GITRL) in patients with rheumatoid arthritis (RA) and investigate its clinical significance. GITRL levels were measured by enzyme-linked immunosorbent assay (ELISA) in 88 RA patients, 20 osteoarthritis (OA) patients, and 20 healthy controls (HCs). Anti-cyclic citrullinated peptide (anti-CCP) antibodies and rheumatoid factor immunoglobulin G (RF-IgG) were also tested by ELISA. RF-IgM, anti-keratin antibody (AKA), and anti-perinuclear factor (APF) antibodies and the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and immunoglobulins were measured by standard laboratory techniques. The disease activity was evaluated by the 28-joint count Disease Activity Score (DAS28). GITRL concentrations were significantly elevated in both serum and synovial fluid (SF) of RA patients. GITRL levels in RA sera were significantly higher than those in matched SFs. Positive correlations were found between serum GITRL levels and inflammation parameters or autoantibody production. GITRL levels are significantly elevated in RA serum and SF and are positively correlated with autoantibody production in RA, suggesting a role of GITRL in the development of RA. PMID:27098050

  16. GITRL modulates the activities of p38 MAPK and STAT3 to promote Th17 cell differentiation in autoimmune arthritis

    PubMed Central

    Ma, Jie; Wang, Jiemin; Qi, Chen; Rui, Ke; Wang, Yungang; Xu, Huaxi; Lu, Liwei; Wang, Shengjun

    2016-01-01

    The glucocorticoid-induced TNFR family-related protein (GITR) and its ligand play a critical role in the pathogenesis of autoimmune arthritis by enhancing the Th17 cell response, but their molecular mechanisms remain largely unclear. This study aims to define the role of p38 mitogen-activated protein kinases (MAPK) and signal transducer and activator of transcription 3 (STAT3) signaling in GITRL-induced Th17 cells in autoimmune arthritis. We found that the p38 phosphorylation was enhanced by GITRL in activated CD4+T cells, and the p38 inhibitor restrained the GITRL-induced Th17 cell expansion in a dose-dependent manner. Moreover, there was decreased STAT3 activity on Tyr705 and Ser727 with the p38 inhibitor in vitro. Notably, the p38 inhibitor could prevent GITRL-treated arthritis progression and markedly decrease the Th17 cell percentages. The phosphorylation of the Tyr705 site was significantly lower in the GITRL-treated CIA mice administrated with the p38 inhibitor. A significantly higher phosphorylation of p38 was detected in RA patients and had a positive relationship with the serum level of anti-cyclic citrullinated peptide (anti-CCP) antibody. Our findings have indicated that GITRL could promote Th17 cell differentiation by p38 MAPK and STAT3 signaling in autoimmune arthritis. PMID:26657118

  17. Investigation of the human FCRL1, 2, and 4 gene expressions in patients with rheumatoid arthritis.

    PubMed

    Khanzadeh, Ali; Habibagahi, Zahra; Hosseini, Ahmad; Amirghofran, Zahra

    2016-08-01

    The Fc receptor-like (FCRL) molecules have recently been shown to contribute to the pathogenesis of certain autoimmune disorders. In this study, we investigated the expression levels of FCRL1, 2 and 4 in blood mononuclear cells from rheumatoid arthritis patients using real-time PCR. The mRNA of these molecules was detected in 44.4 % (FCRL1), 53.3 % (FCRL2) and 31.1 % (FCRL4) of patients. Comparatively, 31.1 % (FCRL1), 51.1 % (FCRL2) and 26.6 % (FCRL4) of controls expressed these genes. Analysis of gene expressions in FCRL-positive patients demonstrated a lower FCRL4 gene expression in patients compared to controls (P < 0.001). In FCRL2-positive patients, a significant positive correlation between FCRL2 expression and the erythrocyte sedimentation rate (P < 0.001), anti-cyclic citrullinated peptide antibody (P = 0.033) level and disease activity score (DAS28, P = 0.016) was found. In conclusion, decreased FCRL4 expression and association of FCRL2 expression with inflammatory markers and disease activity suggested the contribution of these molecules to RA inflammatory processes. PMID:27193470

  18. Rheumatoid arthritis following PEG-interferon-alfa-2a plus ribavirin treatment for chronic hepatitis C: a case report and review of the literature

    PubMed Central

    2013-01-01

    Background The combination of Pegylated Interferon-alpha (PEG-IFN-α) and ribavirin is the current standard of care for the treatment of HCV infection. Unfortunately, IFN-α may lead to the induction or exacerbation of autoimmune diseases, such as psoriasis, thyroiditis, systemic lupus erythematosus and, rarely, rheumatoid arthritis (RA). Case presentation We report the case of a man affected with chronic hepatitis C (CHC) due to HCV genotype 3a infection, who developed RA after a complete course of PEG-IFN-α and ribavirin. Nine weeks after cessation of antiviral treatment, the patient developed symmetrical polyarthritis, with pain and edema in the wrists, knees, shoulders and metacarpophalangeal joints; magnetic resonance imaging detected initial bone erosions with juxta-articular osteopenia in wrist, knee and hand joints. Anti-cyclic citrullinated peptide (anti-CCP) antibodies were positive. Conclusions Autoimmune diseases, including RA, may occur when treating chronic hepatitis C with PEG-IFN-α and ribavirin; therefore, a close surveillance for the occurrence of autoimmune phenomena should be suggested in the setting of HCV management. PMID:24171974

  19. A multivariate method for meta-analysis and comparison of diagnostic tests.

    PubMed

    Dimou, Niki L; Adam, Maria; Bagos, Pantelis G

    2016-09-10

    We present here an extension of the classic bivariate random effects meta-analysis for the log-transformed sensitivity and specificity that can be applied for two or more diagnostic tests. The advantage of this method is that a closed-form expression is derived for the calculation of the within-studies covariances. The method allows the direct calculation of sensitivity and specificity, as well as, the diagnostic odds ratio, the area under curve and the parameters of the summary receiver operator's characteristic curve, along with the means for a formal comparison of these quantities for different tests. There is no need for individual patient data or the simultaneous evaluation of both diagnostic tests in all studies. The method is simple and fast; it can be extended for several diagnostic tests and can be fitted in nearly all statistical packages. The method was evaluated in simulations and applied in a meta-analysis for the comparison of anti-cyclic citrullinated peptide antibody and rheumatoid factor for discriminating patients with rheumatoid arthritis, with encouraging results. Simulations suggest that the method is robust and more powerful compared with the standard bivariate approach that ignores the correlation between tests. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26940666

  20. Organizing Pneumonia in Rheumatoid Arthritis Patients: A Case-Based Review

    PubMed Central

    Mori, Shunsuke; Koga, Yukinori; Sugimoto, Mineharu

    2015-01-01

    We treated 21 patients with organizing pneumonia (OP) associated with rheumatoid arthritis (RA) or related to biological disease-modifying antirheumatic drugs (DMARDs) at our institution between 2006 and 2014. Among these cases, 3 (14.3%) preceded articular symptoms of RA, 4 (19.0%) developed simultaneously with RA onset, and 14 (66.7%) occurred during follow-up periods for RA. In the case of OP preceding RA, increased levels of anti-cyclic citrullinated peptide antibodies and rheumatoid factor were observed at the OP onset. RA disease activity was related to the development of OP in the simultaneous cases. In the cases of OP developing after RA diagnosis, 10 of 14 patients had maintained low disease activity with biological DMARD therapy at the OP onset, and among them, 6 patients developed OP within the first year of this therapy. In the remaining four patients, RA activity was not controlled at the OP onset. All patients responded well to systemic steroid therapy, but two patients suffered from relapses of articular and pulmonary symptoms upon steroid tapering. In most of the RA patients, DMARD therapy was introduced or restarted during the steroid tapering. We successfully restarted a biological DMARD that had not been previously used for patients whose RA would otherwise have been difficult to control. In this study, we also perform a review of the literature on RA-associated or biological DMARD-related OP and discuss the pathogenesis and management of OP occurring in RA patients. PMID:26543387

  1. A Rare Case of Cardiac Tamponade Induced by Chronic Rheumatoid Arthritis

    PubMed Central

    Yousuf, Tariq; Kramer, Jason; Kopiec, Adam; Bulwa, Zachary; Sanyal, Shuvani; Ziffra, Jeffrey

    2015-01-01

    Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease primarily involving the joint synovium. RA is a systemic disease which has many known extra-articular manifestations. We present a unique case of a patient with long standing RA who presented with a primary complaint of chest and back pain. Echocardiography revealed borderline normal left ventricular function and a large pericardial effusion with the finding of elevated intrapericardial pressure suspicious for cardiac tamponade. Infectious workup was all found to be negative. The presence and elevation of anti-cyclic citrullinated peptide antibody, rheumatoid factor and C-reactive protein (CRP) confirmed the patient was having an active flare-up of RA. It was determined that this flare-up was the cause of the cardiac tamponade. A pericardiocentesis was performed and 850 mL of bloody fluid was drained. The patient remained stable following the pericardiocentesis. At his follow-up visit, repeat echocardiogram showed no signs for pericardial effusion. Although there has been extensive study of RA, there are only a few documented cases noting the occurrence of cardiac tamponade in these patients. Therefore, it is important for the clinician to be aware of and recognize this potentially serious cardiac outcome associated with a common rheumatologic condition. PMID:26251689

  2. A study on FoxP3 and Tregs in paired samples of peripheral blood and synovium in rheumatoid arthritis

    PubMed Central

    Shalini P., Usha; Debnath, Tanya; JVS, Vidyasagar; Kamaraju, Suguna R.; Kancherla, Ravindranath; Chelluri, Lakshmi K.

    2016-01-01

    There is an increasing evidence suggesting the role of fork head boxP3 (FoxP3) in the development and the regulation of CD4+CD25+ Treg cells. T-cell regulatory mechanisms in rheumatoid arthritis patients were evaluated by the contributing factors such as pro-inflammatory cytokines, circulating immune complexes, HLA DR expression, ligand binding biomarkers, FoxP3 expression in paired samples of peripheral blood (PB) and synovial fluid (SF). These cellular responses were further correlated with the humoral immune responses such as anti-cyclic citrullinated peptides IgG (CCP), circulating immune complex-c1q IgG (CIC), immunoglobulin G (IgG) and immunoglobulin M (IgM) of the rheumatoid arthritis factor (RAF). The results suggest a definitive role of Tregs in the homeostatic control because there is an increase in FoxP3 (37%) and HLA-DR (45%) expression in the synovial fluid as compared to PB. Furthermore, humoral responses as a downstream effector mechanism are positively correlated with the pathogenesis of rheumatoid arthritis (RA). A positive relationship exists between quantitative anti-CCP production and the expression of HLA-DR. The study relates an increased and pivotal role of B cell activation in the synovial fluid thereby permitting the need to ablate the targeted B cell immune responses. PMID:26862306

  3. Carbamylated vimentin represents a relevant autoantigen in Latin American (Cuban) rheumatoid arthritis patients.

    PubMed

    Martínez, Goitybell; Gómez, Jorge A; Bang, Holger; Martínez-Gamboa, Lorena; Roggenbuck, Dirk; Burmester, Gerd-Rüdiger; Torres, Barbara; Prada, Dinorah; Feist, Eugen

    2016-06-01

    Smoking produces substances that activate proinflammatory, prothrombotic and vasoconstrictive mediators via posttranslational carbamylation of proteins. As a new consequence of carbamylation, induction of anti-carbamylated autoantibodies were observed in rheumatoid arthritis (RA) patients, sometimes prior to onset of the disease. The overall aim of this study was to characterize the reactivity of different isotypes of autoantibodies against carbamylated antigens of vimentin in relation to established rheumatoid factor (RF), anti-citrullinated protein antibodies (ACPA) and markers of disease activity in a so far largely uncharacterized population of Latin American (Cuban) patients with RA. Antigenic properties of carbamylated vimentin as well as vimentin peptides were analyzed in 101 patients with RA, 50 disease controls and 51 healthy controls. The diagnostic performance was compared with established commercial ELISA rheumatoid factor, anti-cyclic citrullinated peptide antibodies of second generation (anti-CCP2) and anti-mutated citrullinated vimentin (anti-MCV) antibodies. Prevalence of anti-MCV IgG (86 %), anti-carbamylated vimentin (carbVIM) IgG (77 %) and anti-carbamylated MCV (carbMCV) IgG antibodies (65 %) was higher than the classical RF IgM (60 %) and anti-CCP2 IgG (52 %) in this RA cohort. Of note, smoking status was associated with positive IgG antibody reactivity against CCP2 in 75.0 % and against MCV in 90 % of patients. Furthermore, IgM antibody response against carbMCV and carbVIM was observed in 80 and 90.0 % of smokers, respectively. Due to a high sensitivity of the IgM antibody isotype of anti-carbVIM of 85.2 %, the combination of ACPA with anti-carbVIM IgM provided the best diagnostic performance so far achieved in a RA cohort of this ethnic origin. We demonstrate a high prevalence of anti-carbVIM antibodies and correlation with smoking in Latin American (Cuban) RA patients. Anti-carbVIM IgM represents an useful marker in ACPA

  4. Expression of Prostaglandin E2 Enzymes in the Synovium of Arthralgia Patients at Risk of Developing Rheumatoid Arthritis and in Early Arthritis Patients

    PubMed Central

    Newsum, Elize C.; Maijer, Karen I.; van de Sande, Marleen G. H.; Ramwadhdoebe, Tamara H.; van Schaardenburg, Dirkjan; van Baarsen, Lisa G. M.; Korotkova, Marina; Gerlag, Danielle M.; Tak, Paul-Peter; Jakobsson, Per-Johan

    2015-01-01

    Objective Arthralgia may precede the development of synovial inflammation in autoantibody-positive individuals at risk of developing rheumatoid arthritis (RA). A major pathway involved in pain is the prostaglandin (PG) E2 pathway. We investigated this pathway in the synovium of individuals with RA-specific autoantibodies and in early arthritis patients. Methods Nineteen autoantibody-positive individuals (IgM-rheumatoid factor and/or anti-cyclic citrullinated peptide antibodies) with arthralgia (n=15) and/or a positive family history of RA (n=8), who had been prospectively followed for at least 2 years, were included. In addition, we included early arthritis patients (disease-modifying antirheumatic drug naïve) who after 2 years follow up fulfilled classification criteria for RA (n=63), spondyloarthritis (SpA; n=14), or had unclassified arthritis (UA; n=27). In all subjects we assessed pain and performed synovial biopsy sampling by mini-arthroscopy at baseline. Tissue sections were examined by immunohistochemistry to detect and quantify PGE2 pathway enzymes expression levels (mPGES-1; COX-1 and -2; 15-PGDH). Results In both study groups synovial expression of PGE2 enzymes was not clearly related to pain sensation. Expression levels at baseline were not associated with the development of arthritis after follow up (6 out of 19 autoantibody-positive individuals). However, in early SpA patients the expression levels of mPGES-1 and COX-1 were significantly increased compared to RA and UA patients. Conclusion Pain in autoantibody-positive individuals without synovial inflammation who are at risk of developing RA and in early arthritis patients may be regulated by pathways other than the PGE2 pathway or originate at sites other than the synovium. In contrast, in SpA, the PGE2 pathway may be inherently linked to the pathophysiology/etiology of the disease. PMID:26225917

  5. Silibinin Improves the Effects of Methotrexate in Patients with Active Rheumatoid Arthritis: Pilot Clinical Study

    PubMed Central

    Hussain, Saad Abdulrahman; Mortada, Ahmed Hashem; Jasim, Nazar Abdulateef; Gorial, Faiq Isho

    2016-01-01

    Objectives Our study sought to evaluate the effects of silibinin in patients with active rheumatoid arthritis (RA) treated with methotrexate (MTX). Methods We conducted a randomized multi-center, double-blind, placebo-controlled clinical trial over a 16-week treatment period at the Al-Sader and Baghdad Teaching Hospitals in Najaf and Baghdad, respectively. A total of 60 patients (30 of each sex) with active RA, already maintained on 12 mg MTX weekly for at least three consecutive months, were included in the study. Patients were randomly allocated to receive either 120 mg silibinin twice daily or a placebo, combined with their regular MTX regimen. The patients were evaluated by measuring disease activity score using the 28-joint Disease Activity Score, Simple Disease Activity Index, and Health Assessment Questionnaire–Disability Index scores at the start and end of the study. Blood samples were evaluated for the erythrocyte sedimentation rate (ESR), hemoglobin (Hb), high-sensitivity C-reactive protein (hs-CRP), creatine kinase (CK), anti-cyclic citrullinated peptide (CCP), and the serum cytokine levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-8, IL-10, and IL-2. Results Silibinin significantly decreases the already elevated clinical scores compared to placebo treatment. ESR, IL-8, IL-6, TNF-α, anti-CCP, hs-CRP levels were significantly reduced. Additionally, the use of silibinin significantly increases Hb, IL-10, and IL-2 levels. Conclusion Silibinin may improve the effects of MTX on certain biochemical and clinical markers of patients with active RA. PMID:27403238

  6. Increased Serum Levels of Anti-Carbamylated 78-kDa Glucose-Regulated Protein Antibody in Patients with Rheumatoid Arthritis.

    PubMed

    Yu, Hui-Chun; Lai, Pei-Hsuan; Lai, Ning-Sheng; Huang, Hsien-Bin; Koo, Malcolm; Lu, Ming-Chi

    2016-01-01

    The objective of this study was to investigate the presence and titer of anti-carbamylated 78-kDa glucose-regulated protein (anti-CarGRP78) antibody in serum from controls, and patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and primary Sjögren syndrome (pSS). Thirty-three RA patients, 20 SLE patients, 20 pSS patients, and 20 controls were enrolled from our outpatient clinic. GRP78 was cloned and carbamylated. Serum titers of anti- cyclic citrullinated peptides (anti-CCP), anti-GRP78, and anti-CarGRP78 were measured with an enzyme-linked immunosorbent assay. No differences in serum titers of anti-GRP78 antibody in patients with RA, SLE, or pSS compared with the controls were observed. Serum levels of anti-carGRP78 antibody in patients with RA, but not SLE or pSS, were significantly higher compared with the controls (OD405 0.15 ± 0.08 versus 0.11 ± 0.03, p = 0.033). There was a positive correlation between the serum levels of anti-GRP78 antibody, but not anti-CarGRP78 antibody, with the levels of anti-CCP antibody in patients with RA. Both anti-GRP78 and anti-carGRP78 antibodies failed to correlate with C-reactive protein levels in patients with RA. In conclusion, we demonstrated the presence of anti-CarGRP78 antibody in patients with RA. In addition, the serum titer of anti-CarGRP78 antibody was significantly elevated in patients with RA compared with the controls. Anti-CarGRP78 antibody could also be detected in patients with SLE or pSS. PMID:27618024

  7. Practice what you preach? An exploratory multilevel study on rheumatoid arthritis guideline adherence by rheumatologists

    PubMed Central

    Lesuis, N; den Broeder, A A; Hulscher, M E J L; van Vollenhoven, R F

    2016-01-01

    Objectives To assess variation in and determinants of rheumatologist guideline adherence in patients with rheumatoid arthritis (RA), in daily practice. Methods In this retrospective observational study, guideline adherence in the first year of treatment was assessed for 7 predefined parameters on diagnostics, treatment and follow-up in all adult patients with RA with a first outpatient clinic visit at the study centre, from September 2009 to March 2011. Variation in guideline adherence was assessed on parameter and rheumatologist level. Determinants for guideline adherence were assessed in patients (demographic characteristics, rheumatoid factor (RF) and/or anti-cyclic citrullinated peptide antibody (aCCP) positivity, erythrocyte sedimentation rate, erosive disease, comorbidity and the number of available disease modifying anti-rheumatic drug (DMARD) treatment options) and rheumatologists (demographic and practice characteristics, guideline knowledge and agreement, outcome expectancy, cognitive bias, thinking style, numeracy and personality). Results A total of 994 visits in 137 patients with RA were reviewed. Variation in guideline adherence among parameters was present (adherence between 21% and 72%), with referral to the physician assistant as lowest scoring and referral to a specialised nurse as highest scoring parameter. Variation in guideline adherence among rheumatologists was also present (adherence between 22% and 100%). Patient sex, the number of DMARD options, presence of erosions, comorbidity, RF/aCCP positivity, type of patient and the rheumatologists' scientific education status were associated with adherence to 1 or more guideline parameters. Conclusions Guideline adherence varied considerably among the guideline parameters and rheumatologists, showing that there is room for improvement. Guideline adherence in our sample was related to several patient and rheumatologist determinants. PMID:27252892

  8. Immune Complexes in Juvenile Idiopathic Arthritis

    PubMed Central

    Moore, Terry L.

    2016-01-01

    Juvenile idiopathic arthritis (JIA) reflects a group of clinically heterogeneous, autoimmune disorders in children characterized by chronic arthritis and hallmarked by elevated levels of circulating immune complexes (CICs) and associated complement activation by-products in their sera. Immune complexes (ICs) have been detected in patients’ sera with JIA utilizing a variety of methods, including the anti-human IgM affinity column, C1q solid-phase assay, polyethylene glycol precipitation, Staphylococcal Protein A separation method, anti-C1q/C3 affinity columns, and FcγRIII affinity method. As many as 75% of JIA patients have had IC detected in their sera. The CIC proteome in JIA patients has been examined to elucidate disease-associated proteins that are expressed in active disease. Evaluation of these ICs has shown the presence of multiple peptide fragments by SDS-PAGE and 2-DE. Subsequently, all isotypes of rheumatoid factor (RF), isotypes of anti-cyclic citrullinated peptide (CCP) antibodies, IgG, C1q, C4, C3, and the membrane attack complex (MAC) were detected in these IC. Complement activation and levels of IC correlate with disease activity in JIA, indicating their role in the pathophysiology of the disease. This review will summarize the existing literature and discuss the role of possible protein modification that participates in the generation of the immune response. We will address the possible role of these events in the development of ectopic germinal centers that become the secondary site of plasma cell development in JIA. We will further address possible therapeutic modalities that could be instituted as a result of the information gathered by the presence of ICs in JIA. PMID:27242784

  9. Rheumatoid Arthritis in the Women's Health Initiative: Methods and Baseline Evaluation

    PubMed Central

    Kuller, Lewis H.; Mackey, Rachel H.; Walitt, Brian T.; Deane, Kevin D.; Holers, V. Michael; Robinson, William H.; Sokolove, Jeremy; Chang, Yuefang; Moreland, Larry W.

    2014-01-01

    Second-generation assays for anti-cyclic citrullinated peptide (anti-CCP), a highly sensitive and specific marker for rheumatoid arthritis (RA), have redefined the epidemiology of RA. In the Women's Health Initiative (WHI) RA study (2009–2011), we evaluated the prevalence of anti-CCP positivity among 15,691 (10.2% of 161,808) WHI participants aged 50–79 years who reported RA. Using stored baseline specimens, we measured serum anti-CCP, rheumatoid factor (RF), and antinuclear antibody in a defined sample of 9,988 of black, white, and Hispanic women. In a subset of women, we measured plasma cytokine levels and number of copies of the human leukocyte antigen (HLA)-DRB1 (HLA-DRB1) shared epitope in DNA by means of Luminex polymerase chain reaction typing (Luminex Corporation, Austin, Texas). We validated classification of probable clinical RA in 2 clinics as anti-CCP positivity or self-reported validated use of disease-modifying antirheumatic drugs (DMARDs). The prevalence of anti-CCP positivity was 8.1%, and the prevalence of RF positivity was approximately 16.0%. DMARD use including prednisone was reported by 1,140 (11.4%) participants (841 excluding prednisone) but by 57.5% of anti-CCP-positive women. The prevalence of 2 shared epitopes was also much higher for anti-CCP-positive women (18.2%, as opposed to only 5.5% for women with anti-CCP-negative DMARD-positive RA and 6.6% for anti-CCP-negative, RF-negative DMARD nonusers). Median cytokine levels were much higher for anti-CCP-positive/RF-positive women. Women with anti-CCP-positive RA and anti-CCP-negative RA had different characteristics with regard to HLA shared epitope, cigarette smoking, and inflammation (cytokines). PMID:24569640

  10. Plasma n-3 fatty acids and clinical outcomes in recent-onset rheumatoid arthritis.

    PubMed

    Proudman, Susanna M; Cleland, Leslie G; Metcalf, Robert G; Sullivan, Thomas R; Spargo, Llewellyn D; James, Michael J

    2015-09-28

    A randomised controlled trial (RCT) of high-dose v. low-dose fish oil in recent-onset rheumatoid arthritis (RA) demonstrated that the group allocated to high-dose fish oil had increased remission and decreased failure of disease-modifying anti-rheumatic drug (DMARD) therapy. This study examines the relationships between plasma phospholipid levels of the n-3 fatty acids in fish oil, EPA and DHA, and remission and DMARD use in recent-onset RA. EPA and DHA were measured in blood samples from both groups of the RCT. The data were analysed as a single cohort, and Cox proportional hazards models were used to examine relationships between plasma phospholipid (PL) EPA and DHA and various outcome measures. When analysed as a single cohort, plasma PL EPA was related to time to remission, with a one unit increase in EPA (1% total fatty acids) associated with a 12% increase in the probability of remission at any time during the study period (hazard ratio (HR)=1.12; 95% CI 1.02, 1.23; P=0.02). Adjustment for smoking, anti-cyclic citrullinated peptide antibodies and 'shared epitope' HLA-DR allele status did not change the HR. Plasma PL EPA, adjusted for the same variables, was negatively related to time to DMARD failure (HR=0.85; 95% CI 0.72, 0.99; P=0.047). The HR for DHA and time to remission or DMARD failure were similar in magnitude to those for EPA, but not statistically significant. Biomarkers of n-3 status, such as plasma PL EPA, have the potential to predict clinical outcomes relevant to standard drug treatment of RA patients. PMID:26283657

  11. The effectiveness of Echinacea extract or composite glucosamine, chondroitin and methyl sulfonyl methane supplements on acute and chronic rheumatoid arthritis rat model.

    PubMed

    Arafa, Nadia Ms; Hamuda, Hayam M; Melek, Samuel T; Darwish, Sahar K

    2013-03-01

    The study aimed to investigate the effect of the oral administration for 15 days of either Echinacea (E) or genuphil (a composite of chondroitin sulphate, glucosamine and methyl sulfonyl methane [GCM]) nutraceutical supplements on female rat model of acute or chronic arthritis induced by bacterial outer membrane protein (OMP) from faecal flora of healthy and rheumatic humans. Anti-cyclic citrullinated peptide (anti-CCP2), C-reactive protein (CRP) and rheumatoid factor (RF) values increased (p < 0.05) in both arthritic groups as compared to normal values. The rheumatic markers anti-CCP2, CRP and RF values decreased significantly in E- and GCM-treated groups compared to arthritic none-treated acute or chronic groups. The results of RF values of GCM-treated groups in acute and chronic models decreased exhibiting no statistical difference compared with the normal value. Histological examinations of the hind paw sections revealed moderate inflammation, oedema and mild proliferation of synovial cells in acute arthritic rats and more damage to cartilage and bone with severe inflammation in chronic ones. Echinacea acute treated group showed edema with proliferated synovial membrane and partial damage in cartilage and bone. While in the E-chronic treated group, rough edge with destructed cartilage and bone existed. However, the acute GCM group revealed mild cartilage damage. But the chronic GCM group showed mild synovial cells proliferation and revealed no inflammation with mild cartilage damage edge. Results demonstrated the OMP arthropathic property and through promising light on arthritis treatment using E- or GCM, with the advantage of GMC results over that of E-. The composite GCM is needed for further studies over the dose and duration to assess its preventive effects against the bacterial OMP arthrogenicity. PMID:22173958

  12. Routine use of Zenit RA, a novel chemiluminescent immunoanalyzer in autoimmune disease diagnosis.

    PubMed

    Ghillani, P; Dufat, L; Himeur, S; Miyara, M; Amoura, Z; Musset, L

    2012-04-01

    The detection of antibodies is useful to diagnose and/or to classify autoimmune diseases as connective tissue diseases and vasculitis. Zenit RA is a fully automated immunoanalyzer. The aim of this study was to compare the predictive and discriminative performance of the Zenit RA anti-cyclic citrullinated peptide (CCP), anti-cardiolipin (aCL) and anti-β 2 glycoprotein 1 (aB2GP1) tests to conventional ELISAs on clinically well-defined groups of patients and to daily evaluate the determination of anti-extractable nuclear antigen (ENA), anti-double stranded DNA (dsDNA), anti-myeloperoxidase (MPO) and anti-proteinase 3 (PR3) antibodies in a hospital laboratory. Reagents available on Zenit RA analyzer exhibit good diagnostic performances, regarding sensitivity, specificity, positive and negative predictive values. Global agreements between Zenit RA and conventional tests were from 90 to 98 % (Kappa-values ranging 0.56-0.94): 96 % for anti-CCP, 90-94 % for aCL and aB2GP1, 94 % for anti-dsDNA, 97 % for anti-ENA, 98 % for anti-MPO and 95 % for anti-PR3 antibodies. Zenit RA analyzer is easy to rapidly detect the most common autoantibodies in autoimmune diseases. This system has a potential to provide clinically useful data within a short time. Because of the flexibility of its work modalities, it is well adapted to determine antigenic specificities in daily practice. PMID:26000125

  13. Inflammatory cytokine levels, disease activity, and function of patients with rheumatoid arthritis treated with combined conventional disease-modifying antirheumatic drugs or biologics.

    PubMed

    Osiri, Manathip; Wongpiyabovorn, Jongkonnee; Sattayasomboon, Youwanuch; Thammacharoenrach, Niramol

    2016-07-01

    The objective of this study was to compare the effects of treatment by combined conventional disease-modifying antirheumatic drugs (cDMARDs) or biologics on cytokines, disease activity, and function in rheumatoid arthritis (RA). Sera from a cohort of 81 patients with long-standing RA treated with combined cDMARDs or biologics were measured for 12 cytokines. Comparisons of serum cytokine concentrations with treatment types (combination 2, 3 cDMARDs or biologics), serologic status (positivity for RF and anti-cyclic citrullinated peptide antibody (anti-CCP Ab)), DAS28-ESR, and function were performed. Spearman correlation coefficients between individual cytokines and clinical parameters were explored. Approximately half of the patients were prescribed two cDMARDs. Mean duration of current treatment was 42 months. More than 70 % had moderate disease activity or normal function/slight disability. Serum concentrations of interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-17A, IL-23, IL-33, interferon (IFN)-γ, granulocyte monocyte-colony stimulating factor (GM-CSF), and TNF-α in patients taking combined cDMARDs did not significantly differ from those on biologics. Seventy-nine serum samples (97.5 %) had undetectable levels of 1 to 10 cytokines. Concentrations of several cytokines were significantly higher in patients with moderate to high disease activity, seropositive or poor functional status. Weak correlations between cytokine levels and RA disease activity or function were demonstrated. The highest correlation coefficients were observed with IL-33, IL-8, and IL-6. Long-term treatment with cDMARDs did not differ from biologics with respect to cytokine concentrations, disease activity, and function. The cytokine profiles in established RA were mainly those produced from effector cells, especially IL-6, IL-8, and IL-33. Both IL-8 and IL-33 may be potential biomarkers and/or treatment targets in patients with late RA. PMID:27188857

  14. Association of PTPN22 1858C→T polymorphism, HLA-DRB1 shared epitope and autoantibodies with rheumatoid arthritis.

    PubMed

    Raslan, Hala M; Attia, Hanaa R; Salama, Iman; Ibrahim, Mona Hamed; Hassan, Eman Mahmoud; El Hussieny, Mohamed S; El Menyawi, Manal M; Amr, Khalda S

    2016-08-01

    To assess impact of PTPN22 1858C→T polymorphism, HLA shared epitope and autoantibodies on susceptibility and severity of rheumatoid arthritis (RA). A total of 150 RA patients and 150 controls were included in the study. Anti-cyclic citrullinated peptide (anti-CCP) and rheumatoid factor isotypes (IgG, IgM and IgA) were assayed by ELISA. PTPN22 1858C→T polymorphism was performed by RFLP analysis and HLA-DRB1 genotyping by PCR-SSP analysis. Single-view, anteroposterior radiographs of the hands and feet were obtained on all RA patients. The results showed association of PTPN22 1858 T allele with RA (OR = 2.3, 95 % CI 1.5-3.5) and bone erosion (OR = 2.9, 95 % CI 1.1-7.6). The associations increased with the combination of positive autoantibodies, HLA-DRB1 SE with PTPN22 1858 T allele carriage. The highest association was with the combination with anti-CCP antibodies (OR = 47.3, 95 % CI 10.9-204.4 for RA and OR = 69.4, 95 % CI 15.8-305.5 for erosion p < 0.001). Combination of PTPN22 1858 T allele carriage with negative RF isotypes or with absence HLA-DRB1 SE showed no significant association with RA. The presence of PTPN22 1858C→T polymorphism with HLA SE and autoantibodies increases risk of RA development and erosive disease. PMID:27324632

  15. Immune Complexes in Juvenile Idiopathic Arthritis.

    PubMed

    Moore, Terry L

    2016-01-01

    Juvenile idiopathic arthritis (JIA) reflects a group of clinically heterogeneous, autoimmune disorders in children characterized by chronic arthritis and hallmarked by elevated levels of circulating immune complexes (CICs) and associated complement activation by-products in their sera. Immune complexes (ICs) have been detected in patients' sera with JIA utilizing a variety of methods, including the anti-human IgM affinity column, C1q solid-phase assay, polyethylene glycol precipitation, Staphylococcal Protein A separation method, anti-C1q/C3 affinity columns, and FcγRIII affinity method. As many as 75% of JIA patients have had IC detected in their sera. The CIC proteome in JIA patients has been examined to elucidate disease-associated proteins that are expressed in active disease. Evaluation of these ICs has shown the presence of multiple peptide fragments by SDS-PAGE and 2-DE. Subsequently, all isotypes of rheumatoid factor (RF), isotypes of anti-cyclic citrullinated peptide (CCP) antibodies, IgG, C1q, C4, C3, and the membrane attack complex (MAC) were detected in these IC. Complement activation and levels of IC correlate with disease activity in JIA, indicating their role in the pathophysiology of the disease. This review will summarize the existing literature and discuss the role of possible protein modification that participates in the generation of the immune response. We will address the possible role of these events in the development of ectopic germinal centers that become the secondary site of plasma cell development in JIA. We will further address possible therapeutic modalities that could be instituted as a result of the information gathered by the presence of ICs in JIA. PMID:27242784

  16. Prevalence of Anti-Peptidylarginine Deiminase Type 4 Antibodies in Rheumatoid Arthritis and Unaffected First-Degree Relatives in Indigenous North American Populations

    PubMed Central

    Ferucci, Elizabeth D.; Darrah, Erika; Smolik, Irene; Choromanski, Tammy L.; Robinson, David B.; Newkirk, Marianna M.; Fritzler, Marvin J.; Rosen, Antony; El-Gabalawy, Hani S.

    2013-01-01

    Objective The objective of this study was to determine whether anti-peptidylarginine deiminase type 4 (PAD4) antibodies were present in first-degree relatives of rheumatoid arthritis (RA) patients in two indigenous North American populations with high prevalence of RA. Methods Participants were recruited from two indigenous populations in Canada and the United States, including RA patients (probands), their unaffected first-degree relatives, and healthy unrelated controls. Sera were tested for the presence of anti-PAD4 antibodies, anti-cyclic citrullinated peptide (CCP) antibodies, and rheumatoid factor (RF). HLA-DRB1 subtyping was performed and participants were classified according to number of shared epitope alleles present. Results Antibodies to PAD4 were detected in 24 of 82 (29.3%) probands; 2 of 147 (1.4%) relatives; and no controls (p <0.0001). Anti-CCP was present in 39/144 (27.1%) of the relatives, and there was no overlap between positivity for anti-CCP and PAD4 in the relatives. In RA patients, anti-PAD4 antibodies were associated with disease duration (p=0.0082) and anti-CCP antibodies (p=0.008), but not smoking or shared epitope alleles. Conclusion Despite a significant prevalence of anti-CCP in first-degree relatives, anti-PAD4 antibodies were almost exclusively found in established RA. The prevalence of anti-PAD4 antibodies in RA is similar to the prevalence described in other populations and these autoantibodies are associated with disease duration and anti-CCP in RA. PMID:23908443

  17. Increased expression of activation-induced cytidine deaminase is associated with anti-CCP and rheumatoid factor in rheumatoid arthritis

    PubMed Central

    Xu, Xin; Hsu, Hui-Chen; Chen, Jian; Grizzle, William E.; Chatham, W. Winn; Stockard, Cecil R.; Wu, Qi; Yang, PingAr; Holers, V. Michael; Mountz, John D.

    2013-01-01

    Rheumatoid arthritis (RA) is associated with higher levels of autoantibodies and IL-17. Here, we investigated if ectopic lymphoid follicles and peripheral blood mononuclear cells (PBMCs) from RA patients exhibit increased activation-induced cytidine deaminase (AID), and if increased AID is correlated with serum levels of autoantibodies and IL-17. The results of immunohistochemical staining showed that organized germinal centers were observed in 6 of the 12 RA synovial samples, and AID+ cells were found almost exclusively in the B-cell areas of these follicles. Aggregated but not organized lymphoid follicles were found in only one OA synovial sample without AID+ cells. Significantly higher levels of AID mRNA (Aicda) detected by RT-PCR were found in the PBMCs from RA patients than PBMCs from normal controls (p<0.01). In the PBMCs from RA patients, AID was expressed predominately by the CD10+IgM+CD20+ B-cell population and the percentage of these cells that expressed AID was significantly higher than in normal controls (p < 0.01). Aicda expression in the PBMCs correlated significantly and positively with the serum levels of rheumatoid factor (RF) (p ≤ 0.0001) and anti-cyclic citrullinated peptide (CCP) (p = 0.0005). Serum levels of IFN-γ (p = 0.0005) and IL-17 (p = 0.007), but not IL-4, also exhibited positive correlation with the expression of AID. These results suggest that the higher levels of AID expression in B cells of RA patients correlate with, and may be associated with the higher levels of T helper cell cytokines IFN-γ and IL-17, leading to the development of anti-CCP and RF. PMID:19703021

  18. Prevalence of overweight in Moroccan patients with rheumatoid arthritis and its relationships with disease features.

    PubMed

    Ibn Yacoub, Yousra; Amine, Bouchra; Laatiris, Assia; Wafki, Fahd; Znat, Fatima; Hajjaj-Hassouni, Najia

    2012-03-01

    We aimed to estimate the prevalence of overweight in Moroccan patients with rheumatoid arthritis (RA) and its relationships with disease activity, functional disability, structural damage, and immunological status. Two hundred fifty patients with RA were consecutively included. Patients' characteristics were specified. The following data were collected: age, disease duration, disease activity (evaluated with physical examination data, biological tests (erythrocyte sedimentation rate and C-reactive protein), and the disease activity score (DAS28)), radiographic changes (assessed by the Sharp's method), functional disability (assessed by using the Health Assessment Questionnaire), extra-articular manifestations, immunological status, and treatment details. Overweight was defined according to the body mass index (BMI) values: underweight, <18.5; normal weight, 18.5-24.9; overweight, 25-29.9; and obesity, ≥30. The mean age of patients was 46.31 ± 12.64 years. The mean disease duration was 9.46 ± 8.43 years. Seventy-five patients (30%) were overweight, 42 (16.8%) were obese, and 133 (53.2%) were normal. Increased BMI was associated with the activity of disease (DAS28) (r = 0.426), structural damage (Sharp total score) (r = 0.297), the rate of rheumatoid factor (r = 0.311), and with the rate of anti-cyclic citrullinated protein antibodies (for all p ≤ 0.01). There were no statistically significant differences in BMI according to gender, dose and duration of corticosteroids, or functional impairment. In our sample, overweight seems to be prevalent in our RA patients. Overweight seems to occur independently of treatment and shown to be mainly associated to disease activity, structural damage, and immunological status. Large studies are needed to confirm those results. PMID:22042491

  19. Interleukin-34 in rheumatoid arthritis: potential role in clinical therapy

    PubMed Central

    Zhang, Fangze; Ding, Rui; Li, Ping; Ma, Cuili; Song, Ding; Wang, Xuetong; Ma, Tianjiao; Bi, Liqi

    2015-01-01

    Objective: To investigate, whether interleukin (IL)-34 can be used as marker for treatment effectiveness in rheumatoid arthritis (RA). Methods: Serum samples were collected from 35 healthy participants and 83 patients with RA before as well as 4 weeks and 12 weeks after treatment initiation with the tumor necrosis factor α (TNF-α) inhibitor Etanercept. Related clinical data and hand radiograms of the patients were evaluated and serum IL-34, IL-6, IL-8, TNF-α, matrix metalloproteinase-3 (MMP-3) in addition to anti-cyclic citrullinated peptide (CCP) antibody concentrations were measured by ELISA. Results: Serum concentrations of IL-34, IL-6, IL-8, TNF-α, MMP-3 and anti-CCP antibodies were markedly elevated in RA patients compared with controls (P<0.001), significantly decreased during treatment and correlated with erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and RA disease activity (P<0.05). IL-34 correlated withIL-6, IL-8, TNF-α, MMP-3 and anti-CCP antibodies in RA patients at baseline (P<0.01) and also with IL-8, MMP-3, IL-6, and DAS28 changes during therapy. Patients in stage III of hand X-ray RA scores had higher IL-34 serum concentrations than in stage II (P<0.05). IL-34 level decreased significantly (P<0.01) starting from 4 weeks after therapy initiation. Conclusions: IL-34 serum concentrations correlated with inflammatory cytokines before and during therapy and were significantly higher in stage III of hand X-ray score patients than in stage II participants. IL-34 might be used both as a biomarker for RA diagnosis and therapy efficiency. PMID:26221333

  20. Serum Immunoglobulin G Levels to Porphyromonas gingivalis Peptidylarginine Deiminase Affect Clinical Response to Biological Disease-Modifying Antirheumatic Drug in Rheumatoid Arthritis

    PubMed Central

    Kobayashi, Tetsuo; Ito, Satoshi; Kobayashi, Daisuke; Shimada, Atsushi; Narita, Ichiei; Murasawa, Akira; Nakazono, Kiyoshi; Yoshie, Hiromasa

    2016-01-01

    Objectives To determine whether serum immunity to Porphyromonas gingivalis peptidylarginine deiminase (PPAD) affects the clinical response to biological disease-modifying antirheumatic drug (bDMARD) in patients with rheumatoid arthritis (RA). Methods In a retrospective study, rheumatologic and periodontal conditions of 60 patients with RA who had been treated with conventional synthetic DMARD were evaluated before (baseline) and after 3 and 6 months of bDMARD therapy. After serum levels of anti-PPAD immunoglobulin G (IgG) were determined at baseline, the patients were respectively divided into two groups for high and low anti-PPAD IgG titers according to the median measurements. Genotypes at 8 functional single nucleotide polymorphisms (SNPs) related to RA were also determined. Results After 3 and 6 months of therapy, patients with low anti-PPAD IgG titers showed a significantly greater decrease in changes in the Disease Activity Score including 28 joints using C-reactive protein (DAS28-CRP) (P = 0.04 for both) and anti-cyclic citrullinated peptide (CCP) IgG levels (P = 0.03 and P = 0.04) than patients with high anti-PPAD IgG titers, although these parameter values were comparable at baseline. The anti-PPAD IgG titers were significantly positively correlated with changes in the DAS28-CRP (P = 0.01 for both) and the anti-CCP IgG levels (P = 0.02 for both) from baseline to 3 and 6 months later. A multiple regression analysis revealed a significantly positive association between the anti-PPAD IgG titers and changes in the DAS28-CRP after 6 months of bDMARD therapy (P = 0.006), after adjusting for age, gender, smoking, periodontal condition, and RA-related SNPs. Conclusion The serum IgG levels to PPAD affect the clinical response to bDMARD in patients with RA. PMID:27111223

  1. Effect of galantamine on adjuvant-induced arthritis in rats.

    PubMed

    Gowayed, Mennatallah A; Refaat, Rowaida; Ahmed, Walid M; El-Abhar, Hanan S

    2015-10-01

    Stimulation of the vagus nerve suppresses cytokine production and macrophage activation, via the interaction of its neurotransmitter acetylcholine (ACh) with the α7 subunit of the nicotinic acetylcholine receptor (α7nAChR), present on neurons and inflammatory cells. The present study aimed to verify the potential anti-inflammatory effect of galantamine against experimental arthritis induced in rats. Fourteen days post adjuvant injection, Sprague-Dawley rats were treated orally with three doses of galantamine (1.25, 2.5 and 5 mg/kg) or leflunomide (10 mg/kg) for 2 weeks and arthritis progression was assessed by hind paw swelling. Additionally, serum biomarkers, viz., anti-cyclic citrullinated peptide antibodies (Anti-CCP), tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10) and monocyte chemoattractant protein-1 (MCP-1) were measured. Radiological examination of the hind paws was also carried out to evaluate the degree of joint damage. Adjuvant arthritis led to a significant weight loss, marked swelling of the hind paw and alteration in the serum levels of anti-CCP, TNF-α, IL-10 and MCP-1. These alterations were associated with significant radiological changes of the joints. Galantamine, in a dose-dependent manner, reduced significantly all biomarkers of inflammation, with the highest dose showing the best beneficial anti-inflammatory effect that was superior in magnitude to the reference drug leflunomide in most of the studied parameters. In conclusion, these results suggest that galantamine may represent a novel, inexpensive and effective therapeutic strategy in the treatment of rheumatoid arthritis. PMID:26189022

  2. Are patient questionnaire scores as "scientific" as laboratory tests for rheumatology clinical care?

    PubMed

    Pincus, Theodore

    2010-01-01

    Modern medical care is based largely on laboratory advances, such as microbiological cultures giving rise to antibiotics and hemoglobin A1c leading to "tight control" of diabetes, among many others. Development of a "gold standard" laboratory test has appeared attractive for care of patients with rheumatoid arthritis (RA) since rheumatoid factor was identified in the 1940s. Indeed, rheumatoid factor, anti-cyclic citrullinated peptide (anti-CCP) antibodies, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) are abnormal in most RA patients. However, each of these tests is normal in at least 30% of patients, and no laboratory test (or any other measure) can serve as a single "gold standard" measure for all individual RA patients. A new approach to quantitative assessment in rheumatic diseases involves patient self-report questionnaires as standardized, quantitative, cost-effective "scientific" data from a medical history, the primary source of RA management decisions. Patient questionnaires distinguish active from control treatments in RA clinical trials at levels similar to laboratory tests (or formal joint counts), and are far more significant in the prognosis of work disability, costs, and premature death than laboratory tests or radiographic scores. RAPID3 (routine assessment of patient index data) on an MDHAQ (multidimensional health assessment questionnaire) requires 5 seconds to score, compared to 114 seconds for a DAS28 (disease activity score). Patient questionnaires do not replace further medical history, physical examination, laboratory or other tests, and require physician interpretation for patient management, as do laboratory tests and all quantitative data. Advances in therapy require laboratory science, but patient questionnaires provide optimal "scientific" data for clinical care. PMID:20632989

  3. A Transmembrane Polymorphism of Fcγ Receptor IIb Is Associated with Kidney Deficiency Syndrome in Rheumatoid Arthritis

    PubMed Central

    Mo, Na; Lai, Ruogu; Luo, Shizi; Xie, Jianglin; Wang, Xizi; Liu, Lijuan; Liu, Xiaoling

    2016-01-01

    Objective. The purpose is to investigate the role of kidney deficiency and the association between kidney deficiency and a polymorphism FcγRIIb 695T>C coding for nonsynonymous substitution IIe232Thr (I232T) in rheumatoid arthritis (RA). Methods. Clinical parameters and autoantibodies were analyzed and genotyping was performed in 159 kidney deficiency and 161 non-kidney-deficiency RA patients. Results. The age of disease onset and disease duration exhibited significant differences between two groups (P < 0.01). Patients with kidney deficiency tend to have higher activity of disease (P < 0.05). Anti-cyclic citrullinated peptides antibodies (ACPA) levels of patients with kidney deficiency were higher than the controls (P = 0.039). 125 (78.6%) kidney deficiency and 114 (70.8%) non-kidney-deficiency patients had both ACPA-positive and RF-positive (P = 0.04, OR = 3.29). FcγRIIb I232TT homozygotes were identified in 10 of 159 (6.3%) kidney deficiency subjects and 1 of 161 (0.6%) controls (P = 0.000, OR = 16.45). Furthermore, in pooled genotype analysis, I232IT and I232TT homozygotes were significantly enriched in kidney deficiency individuals compared with the controls (P = 0.000, OR = 3.79). Frequency of T allele was associated with kidney deficiency RA population (P = 0.000, OR = 3.18). Conclusion. This study confirmed that kidney deficiency was closely associated with disease activity and autoimmune disorder in RA. Kidney deficiency in RA is first to reveal a strong genetic link to FcγRIIb variants. PMID:27051449

  4. Association of rs6822844 within the KIAA1109/TENR/IL2/IL21 locus with rheumatoid arthritis in the Algerian population.

    PubMed

    Louahchi, S; Allam, I; Raaf, N; Berkani, L; Boucharef, A; Abdessemed, A; Khaldoun, N; Bahaz, N; Ladjouze-Rezig, A; Nebbab, A; Ghaffor, M; Djidjik, R

    2016-03-01

    Increasing evidence suggests that the rs6822844, within KIAA1109/TENR/IL2/IL21 gene cluster on 4q27, is strongly associated with rheumatoid arthritis (RA) in the Caucasian population. The aim of this study is to investigate the possible association between the SNP rs6822844 and susceptibility to RA in the Algerian Maghreb population, and to explore the association with the clinical and immunological features of RA. The polymorphism rs6822844 was genotyped in 323 RA patients and 323 healthy individuals using the TaqMan assay. A strong association of IL2/IL21 with RA susceptibility was detected in the Algerian population [odds ratio (OR) = 2.57 (95% confidence interval (CI) 1.74-3.83), P = 10(-4) ]. Our results revealed that IL2/IL21 predisposed to disease development in both autoantibody positive and negative disease. Meanwhile, the association was stronger in RA patients with anti-cyclic citrullinated peptides (ACPA) positive than those with ACPA negative [OR = 2.30 (95% CI 1.53-3.51), P = 10(-4) and OR = 1.98 (95% CI 1.01-4.22), P = 0.037, respectively]. Moreover, our findings showed a moderate association of the rs6822844 polymorphism with disease activity (P = 0.014). This study indicates for the first time that there is a strong association between IL2/IL21 rs6822844 variant and susceptibility to RA in the Algerian population, and that this association was independent from the autoantibodies status of RA patients. PMID:26917059

  5. Polyarthritis in primary Sjögren's syndrome represents a distinct subset with less pronounced B cell proliferation a Dutch cohort with long-term follow-up.

    PubMed

    Ter Borg, E J; Kelder, J C

    2016-03-01

    The primary goal was to investigate the differences in patients with and without polyarthritis (PA) in primary Sjögren's syndrome (pSS) in a clinical-based (real-life) setting, with respect to demographic characteristics, cumulative prevalence of other extra-glandular manifestations (EGM), hypergammaglobulinaemia and serological profile. The secondary goal was to describe the characteristics of polyarthritis in our pSS cohort. Patients diagnosed with pSS and polyarthritis but without rheumatoid arthritis (RA)-like changes on X-rays were followed up prospectively from June 1991 until August 2014, with at least one check-up each year. Patients fulfilling the criteria for concomitant connective tissue disorders were excluded. Data were collected with respect to the prevalence of systemic auto-antibodies (anti-nuclear antibodies (ANA), anti-Sjögren's syndrome-related antigen A (anti-SSA), anti-Sjögren's syndrome type B (anti-SSB) and immunoglobulin M-rheumatoid factor (IgM-RF)) and other EGM related to pSS. A total of 134 patients were included for the final analysis. The median follow-up was 86 months (range 0-368 months). Twenty-two patients (16.4 %) had polyarthritis. The prevalence of systemic auto-antibodies including rheumatoid factor did not differ between the two groups. Anti-cyclic citrullinated peptide (CCP) occurred much more frequently in the polyarthritis-positive (PA+) patients (13.7 vs 0.9 %; p = 0.015). Hypergammaglobulinaemia (p = 0.002) and increased levels of IgG (p = 0.013) occurred much less frequently in the PA+ group compared to the polyarthritis-negative (PA-) group. The mean total number of EGM or of any specific EGM did not differ between the two groups. Most patients had a mild, symmetrical PA predominantly involving the finger joints (proximal interphalangeal joints/metacarpophalangeal joints (PIP/MCP)) and/or wrists and/or metatarsophalangeal (MTP) joints. Significant morning stiffness lasting ≥1 h was found

  6. Current smoking status is a strong predictor of radiographic progression in early rheumatoid arthritis: results from the SWEFOT trial

    PubMed Central

    Saevarsdottir, Saedis; Rezaei, Hamed; Geborek, Pierre; Petersson, Ingemar; Ernestam, Sofia; Albertsson, Kristina; Forslind, Kristina; van Vollenhoven, Ronald F

    2015-01-01

    Objectives To study clinical predictors for radiographic progression after 1 year in an early rheumatoid arthritis (RA) trial. Methods In the SWEFOT trial population, disease modifying antirheumatic drug (DMARD) naïve RA patients started methotrexate; 3-month responders (DAS28 <3.2) continued (n=147), while non-responders were randomised to addition of sulfasalazine+hydroxychloroquine (n=130) or infliximab (n=128). X-rays were scored by the Sharp-van der Hejde score (SHS) method and radiographic progression was defined as a ≥5 increase after 1 year. Potential baseline predictors of radiographic progression were tested using multivariable logistic regression, adjusted for potential confounders. Results 79 of 311 patients with available radiographs at baseline and follow-up had radiographic progression. The following baseline parameters were independent predictors of radiographic progression at 1 year: baseline erosions (adjusted OR=2.29, 95% CI 1.24 to 4.24), erythrocyte sedimentation rate (adjusted OR per tertile increase=1.72, 95% CI 1.12 to 2.65) and C-reactive protein (adjusted OR per tertile increase=1.52, 95% CI 1.03 to 2.26). Current smoking was an independent predictor of radiographic progression (adjusted OR=2.17, 95% CI 1.06 to 4.45). These results remained after further adjustment for treatment strategy. Three-dimensional matrix including current smoking status, erosions and C-reactive protein tertiles showed a 12–63% risk gradient from patients carrying none compared with all predictors. Rheumatoid factor (RF)/anti-cyclic citrullinated peptide (anti-CCP) positivity did not significantly predict radiographic progression using SHS increase ≥5 as cut-off. In a secondary exploratory analysis using cut-off >1, both RF and anti-CCP positivity were significant predictors in the unadjusted, but not the adjusted analyses. The other parameters also remained significant using this lower cut-off. Conclusions In addition to previously described

  7. Interleukin 15 Levels in Serum May Predict a Severe Disease Course in Patients with Early Arthritis

    PubMed Central

    González-Álvaro, Isidoro; Ortiz, Ana M.; Alvaro-Gracia, José María; Castañeda, Santos; Díaz-Sánchez, Belen; Carvajal, Inmaculada; García-Vadillo, J. Alberto; Humbría, Alicia; López-Bote, J. Pedro; Patiño, Esther; Tomero, Eva G.; Vicente, Esther F.; Sabando, Pedro; García-Vicuña, Rosario

    2011-01-01

    Background Interleukin-15 (IL-15) is thought to be involved in the physiopathological mechanisms of RA and it can be detected in the serum and the synovial fluid of inflamed joints in patients with RA but not in patients with osteoarthritis or other inflammatory joint diseases. Therefore, the objective of this work is to analyse whether serum IL-15 (sIL-15) levels serve as a biomarker of disease severity in patients with early arthritis (EA). Methodology and Results Data from 190 patients in an EA register were analysed (77.2% female; median age 53 years; 6-month median disease duration at entry). Clinical and treatment information was recorded systematically, especially the prescription of disease modifying anti-rheumatic drugs. Two multivariate longitudinal analyses were performed with different dependent variables: 1) DAS28 and 2) a variable reflecting intensive treatment. Both included sIL-15 as predictive variable and other variables associated with disease severity, including rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibodies (ACPA). Of the 171 patients (638 visits analysed) completing the follow-up, 71% suffered rheumatoid arthritis and 29% were considered as undifferentiated arthritis. Elevated sIL-15 was detected in 29% of this population and this biomarker did not overlap extensively with RF or ACPA. High sIL-15 levels (β Coefficient [95% confidence interval]: 0.12 [0.06–0.18]; p<0.001) or ACPA (0.34 [0.01–0.67]; p = 0.044) were significantly and independently associated with a higher DAS28 during follow-up, after adjusting for confounding variables such as gender, age and treatment. In addition, those patients with elevated sIL-15 had a significantly higher risk of receiving intensive treatment (RR 1.78, 95% confidence interval 1.18–2.7; p = 0.007). Conclusions Patients with EA displaying high baseline sIL-15 suffered a more severe disease and received more intensive treatment. Thus, sIL-15 may be a biomarker for

  8. The first double-blind, randomised, parallel-group certolizumab pegol study in methotrexate-naive early rheumatoid arthritis patients with poor prognostic factors, C-OPERA, shows inhibition of radiographic progression

    PubMed Central

    Atsumi, Tatsuya; Yamamoto, Kazuhiko; Takeuchi, Tsutomu; Yamanaka, Hisashi; Ishiguro, Naoki; Tanaka, Yoshiya; Eguchi, Katsumi; Watanabe, Akira; Origasa, Hideki; Yasuda, Shinsuke; Yamanishi, Yuji; Kita, Yasuhiko; Matsubara, Tsukasa; Iwamoto, Masahiro; Shoji, Toshiharu; Okada, Toshiyuki; Miyasaka, Nobuyuki; Koike, Takao

    2016-01-01

    Objectives To evaluate efficacy and safety of combination therapy using certolizumab pegol (CZP) and methotrexate (MTX) as first-line treatment for MTX-naive, early rheumatoid arthritis (RA) with poor prognostic factors, compared with MTX alone. Methods MTX-naive, early RA patients with ≤12 months persistent disease, high anti-cyclic citrullinated peptide, and either rheumatoid factor positive and/or presence of bone erosions were enrolled in this multicentre, double-blind, randomised placebo (PBO)-controlled study. Patients were randomised 1:1 to CZP+MTX or PBO+MTX for 52 weeks. Primary endpoint was inhibition of radiographic progression (change from baseline in modified Total Sharp Score (mTSS CFB)) at week 52. Secondary endpoints were mTSS CFB at week 24, and clinical remission rates at weeks 24 and 52. Results 316 patients randomised to CZP+MTX (n=159) or PBO+MTX (n=157) had comparable baseline characteristics reflecting features of early RA (mean disease duration: 4.0 vs 4.3 months; Disease Activity Score 28-joint assessment (DAS28)) (erythrocyte sedimentation rate (ESR)): 5.4 vs 5.5; mTSS: 5.2 vs 6.0). CZP+MTX group showed significantly greater inhibition of radiographic progression relative to PBO+MTX at week 52 (mTSS CFB=0.36 vs 1.58; p<0.001) and week 24 (mTSS CFB=0.26 vs 0.86; p=0.003). Clinical remission rates (Simple Disease Activity Index, Boolean and DAS28 (ESR)) of the CZP+MTX group were significantly higher compared with those of the PBO+MTX group, at weeks 24 and 52. Safety results in both groups were similar, with no new safety signals observed with addition of CZP to MTX. Conclusions In MTX-naive early RA patients with poor prognostic factors, CZP+MTX significantly inhibited structural damage and reduced RA signs and symptoms, demonstrating the efficacy of CZP in these patients. Trial registration number (NCT01451203). PMID:26139005

  9. Evaluation of the rheumatoid arthritis susceptibility loci HLA-DRB1, PTPN22, OLIG3/TNFAIP3, STAT4 and TRAF1/C5 in an inception cohort

    PubMed Central

    2010-01-01

    Introduction This study investigated five confirmed rheumatoid arthritis (RA) susceptibility genes/loci (HLA-DRB1, PTPN22, STAT4, OLIG3/TNFAIP3 and TRAF1/C5) for association with susceptibility and severity in an inception cohort. Methods The magnitude of association for each genotype was assessed in 1,046 RA subjects from the Yorkshire Early RA cohort and in 5,968 healthy UK controls. Additional exploratory subanalyses were undertaken in subgroups defined by autoantibody status (rheumatoid factor and anti-cyclic citrullinated peptide) or disease severity (baseline articular erosions, Health Assessment Questionnaire (HAQ) score and swollen joint count (SJC)). Results In the total RA inception cohort, the HLA-DRB1 shared epitope (per-allele odds ratio (OR) = 2.1, trend P < 0.0001), PTPN22 (per-allele OR = 1.5, trend P < 0.0001), OLIG3/TNFAIP3 locus (per-allele OR = 1.2, trend P = 0.009) and TRAF1/C5 locus (per-allele OR = 1.1, trend P = 0.04) were associated with RA. The magnitude of association for these loci was increased in those patients who were autoantibody-positive. PTPN22 was associated with autoantibody-negative RA (per-allele OR = 1.3, trend P = 0.04). There was no evidence of association between these five genetic loci and baseline erosions or SJC in the total RA cohort, after adjustment for symptom duration. TRAF1/C5 was significantly associated with baseline HAQ, however, following adjustment for symptom duration (P trend = 0.03). Conclusions These findings support the mounting evidence that different genetic loci are associated with autoantibody-positive and autoantibody-negative RA, possibly suggesting that many of the genes identified to date are associated with autoantibody production. Additional studies with a specific focus on autoantibody-negative RA will be needed to identify the genes predisposing to this RA subgroup. The TRAF1/C5 locus in particular warrants further investigation in RA as a potential disease severity locus. PMID:20353580

  10. [Hypercoagulable state is associated with NF-kappa B activation and increased inflammatory factors in patients with rheumatoid arthritis].

    PubMed

    Zhang, Pingheng; Liu, Jian; Tan, Bing; Zhu, Fubing; Fang, Li

    2016-03-01

    Objective To investigate the mechanism of hypercoagulable state based on nuclear factor κB (NF-κB) pathway in patients with rheumatoid arthritis (RA). Methods Thirty-five RA patients were enrolled as well as 20 healthy volunteers as a control group. Interleukin-10 (IL-10), IL-6, IL-4, IL-17, NF-κB activator 1 (Act1), p50, p65, IκBα, platelet activating factor (PAF), PAF-acetylhydrolase (PAF-AH) and anti-cyclic citrullinated peptide (CCP) were detected using ELISA. The number of platelet (PLT) was detected using Sysmex XT-2000i automated hematology analyzer. The levels of D-dimer (D-D), fibrinogen (FBG), thrombin time (TT), prothrombin time (PT), and partial thromboplastin time (APTT) were detected using Sysmex CA-1500 automatic coagulation analyzer. Erythrocyte sedimentation rate (ESR) was detected using Westergren method. C-reactive protein and rheumatoid factor (RF) were detected using Hitachi 7060 automatic biochemical analyzer. Meanwhile, the mRNA expressions of Act1, p65, p50, IκBα and IκB kinase α (IKKα) were detected using semi-quantitative reverse transcription PCR. The expressions of p65, p50 and IκBα proteins were examined using Western blotting. The correlations of the above indexes were analyzed by Spearman correlation test. Results Compared with the normal group, the levels of DD, FBG, PLT significantly increased in the peripheral blood of RA patients, TT decreased, while APTT and PT were not significantly changed. IL-4, IL-10 and PAF-AH were significantly reduced in the sera of RA patients, while IL-6, IL-17, Act1, p50, p65, IκBα, IKKα and PAF were significantly elevated. Spearman correlation analysis showed that coagulant and fibrinolytic indexes were significantly correlated with cytokines, NF-κB, activity indexes and clinical symptoms and signs. Conclusion The hypercoagulable state is common in the peripheral blood of RA patients, and it is closely related to inflammatory factors, activity indexes and abnormal activation of NF

  11. Prevalence of Undiagnosed Diabetes in Rheumatoid Arthritis: an OGTT Study.

    PubMed

    Ursini, Francesco; Russo, Emilio; D'Angelo, Salvatore; Arturi, Franco; Hribal, Marta Letizia; D'Antona, Lucia; Bruno, Caterina; Tripepi, Giovanni; Naty, Saverio; De Sarro, Giovambattista; Olivieri, Ignazio; Grembiale, Rosa Daniela

    2016-02-01

    Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by an excess of cardiovascular disease (CVD) risk, estimated to be at least 50% greater when compared to the general population. Although the widespread diffusion of type 2 diabetes mellitus (T2DM) awareness, there is still a significant proportion of patients with T2DM that remain undiagnosed. Aim of this cross-sectional study was to evaluate the prevalence of undiagnosed diabetes and prediabetes in RA patients. For the present study, 100 consecutive nondiabetic RA patients were recruited. Age- and sex-matched subjects with noninflammatory diseases (osteoarthritis or fibromyalgia) were used as controls. After overnight fasting, blood samples were obtained for laboratory evaluation including serum glucose, total cholesterol, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, triglycerides, uric acid, erythrocyte sedimentation rate (ESR), high sensitivity C-reactive protein (hs-CRP), rheumatoid factor (RF), and anti-Cyclic Citrullinated Peptide Antibodies (ACPA). A standard Oral Glucose Tolerance Test (OGTT) with 75 g of glucose was performed and blood samples were collected at time 0, 30, 60, 90, and 120 minutes, for measurement of plasma glucose concentrations. The prevalence of impaired fasting glucose (IFG) (9/100 vs 12/100, P = 0.49), impaired glucose tolerance (IGT) (19/100 vs 12/100, P = 0.17), and concomitant IFG/IGT (5/100 vs 9/100, P = 0.27) was similar between groups, whereas the prevalence of diabetes was significantly higher in RA patients (10/100 vs 2/100, P = 0.02). In a logistic regression analysis, increasing age (OR = 1.13, 95% CI 1.028-1.245, P = 0.01) and disease duration (OR = 1.90, 95% CI 1.210-2.995, P = 0.005) were both associated with an increased likelihood of being classified as prediabetes (i.e. IFG and/or IGT) or T2DM. A ROC curve was built to evaluate the predictivity of disease duration on the

  12. Risk factors for ANA positivity in healthy persons

    PubMed Central

    2011-01-01

    Introduction The finding of antinuclear antibody (ANA) positivity in a healthy individual is usually of unknown significance and in most cases is benign. However, a subset of such individuals is at risk for development of autoimmune disease. We examined demographic and immunological features that are associated with ANA positivity in clinically healthy persons to develop insights into when this marker carries risk of progression to lupus. Methods Biological samples from healthy individuals and patients with systemic lupus erythematosus (SLE) were obtained from the Dallas Regional Autoimmune Disease Registry (DRADR). Measurements carried out on serum samples included ANA, extractable nuclear antibodies (ENA) and autoantibody profiling using an array with more than 100 specificities. Whole blood RNA samples from a subset of individuals were used to analyze gene expression on the Illumina platform. Data were analyzed for associations of high ANA levels with demographic features, the presence of other autoantibodies and with gene expression profiles. Results Overall, ANA levels are significantly higher in females than in males and this association holds in patients with the autoimmune diseases lupus and rheumatoid arthritis (RA) as well as in healthy controls (HC). Age was not significantly associated with ANA levels and the elevated ANA values could not be explained by higher IgG levels. Another autoantibody, anti- cyclic citrullinated peptide (CCP), did not show gender dimorphism in rheumatoid arthritis (RA) or healthy individuals. The autoantigen array showed significant elevations of other autoantibodies in high ANA HCs. Some of these autoantibodies were directed to antigens in skin and others were related to autoimmune conditions of kidney, thyroid or joints. Gene expression analyses showed a greater prevalence of significantly upregulated genes in HCs with negative ANA values than in those with significant ANA positivity. Genes upregulated in high ANA HCs

  13. The number of elevated cytokines/chemokines in pre-clinical seropositive rheumatoid arthritis predicts time to diagnosis in an age-dependent manner

    PubMed Central

    Deane, Kevin D.; O’Donnell, Colin I.; Hueber, Wolfgang; Majka, Darcy S.; Lazar, Ann A.; Derber, Lezlie A.; Gilliland, William R.; Edison, Jess D.; Norris, Jill M.; Robinson, William H.; Holers, V. Michael

    2010-01-01

    Purpose Pre-clinical rheumatoid arthritis (RA) biomarker elevations were evaluated and utilized to develop a model for the prediction of time to future diagnosis of seropositive RA. Methods Stored samples from 73 military seropositive RA cases (and controls) from pre-RA diagnosis (mean 2.9 samples per case; samples collected a mean of 6.6 years prior-to-diagnosis) were tested for rheumatoid factor (RF) isotypes, anti-cyclic citrullinated peptide (anti-CCP) antibodies, 14 cytokines/chemokines (bead-based assay) and C-reactive protein (CRP). Results Pre-clinical positivity of anti-CCP and/or 2 or more RF isotypes was >96% specific for future RA. In pre-clinical RA, levels of the following were positive in a significantly greater proportion of RA cases versus controls: interleukin (IL)-1α, IL-1β, IL-6, IL-10, IL-12p40, IL-12p70, IL-15, fibroblast growth factor-2, Flt-3 ligand, tumor necrosis factor-α, interferon gamma induced protein-10, granulocyte macrophage colony-stimulating factor, and CRP. Also, increasing numbers of elevated cytokines/chemokines were present in cases nearer to the time of diagnosis. RA cases ≥40 years-old at diagnosis had a higher proportion of samples positive for cytokines/chemokines 5-10 years prior-to-diagnosis, compared to cases <40 at diagnosis (p<0.01). In regression modeling using only case samples positive for autoantibodies highly specific for future RA, increasing numbers of cytokines/chemokines predicted decreased time-to-diagnosis, and the predicted time-to-diagnosis based on cytokines/chemokines was longer in older compared to younger cases. Conclusions Autoantibodies, cytokines/chemokines and CRP are elevated in the pre-clinical period of RA development. In pre-clinical autoantibody positive cases, the number of elevated cytokines/chemokines predicts the time of diagnosis of future RA in an age-dependent manner. PMID:20597112

  14. Fatigue and severity of rheumatoid arthritis in Moroccan patients.

    PubMed

    Ibn Yacoub, Yousra; Amine, Bouchra; Laatiris, Assia; Wafki, Fahd; Znat, Fatima; Hajjaj-Hassouni, Najia

    2012-07-01

    The aim of this study was to assess fatigue aspects in Moroccan patients with rheumatoid arthritis (RA) and its relationships with disease-specific variables especially parameters of functional and structural severity. A total of 248 patients with RA were included. Patients' and disease characteristics were identified. Disease activity was measured clinically using physical examination, biologically and by the disease activity scores (DAS28). Radiographs were evaluated by using Sharp's method as modified by van der Heijde. Functional disability was measured by using the Moroccan version of Health Assessment Questionnaire (HAQ). Immunological abnormalities and treatment (doses and duration) were identified. Fatigue was evaluated by using a 0-100 visual analogue scale (VAS fatigue) and the multidimensional assessment of fatigue (MAF). Quality of life (QoL) was assessed using the Arabic version of the generic instrument SF-36. The mean age of patients was 47.5 ± 11.7 years [25-72]; 37.5% of patients had a high activity of disease and 11.3% were in remission. The mean Sharp score was 107.13 ± 91, and the mean score of HAQ was 1.40 ± 0.63. All domains of QoL were deteriorated; 89.51% of our patients experienced fatigue. The mean total score of MAF was 30.21 ± 11.32. A low level of education, low socioeconomic status, atlantoaxial subluxation, hip involvement, the presence of a Sjögren syndrome, and cigarette smoking had a negative impact on fatigue scores. The severity of fatigue was correlated with the duration of RA, the intensity of joint pain, the activity of disease, the importance of structural damage, the degree of functional impairment, and the rate of anti-cyclic citrullinated protein (CCP) antibodies (P < 0.05). Patients receiving methotrexate had better scores of fatigue. Also, severity of fatigue was correlated with the deterioration of all domains of QoL. Fatigue is a major issue for our patients with RA and must be included in the routine assessment

  15. Baseline Serum Osteopontin Levels Predict the Clinical Effectiveness of Tocilizumab but Not Infliximab in Biologic-Naïve Patients with Rheumatoid Arthritis: A Single-Center Prospective Study at 1 Year (the Keio First-Bio Cohort Study)

    PubMed Central

    Izumi, Keisuke; Kaneko, Yuko; Hashizume, Misato; Yoshimoto, Keiko; Takeuchi, Tsutomu

    2015-01-01

    Objective To explore the baseline predictors of clinical effectiveness after tocilizumab or infliximab treatment in biologic-naïve rheumatoid arthritis patients. Methods Consecutive biologic-naïve patients with rheumatoid arthritis initiating infliximab (n = 57) or tocilizumab (n = 70) treatment were included in our prospective cohort study. Our cohort started in February 2010, and the patients observed for at least 1 year as of April 2013 were analysed. We assessed baseline variables including patients' characteristics (age, sex, disease duration, prednisolone dose, methotrexate dose, other disease-modifying antirheumatic drug use, Clinical Disease Activity Index [CDAI]) and serum biomarker levels (C-reactive protein, immunoglobulin M-rheumatoid factor, anti-cyclic citrullinated protein/peptide antibodies, interferon-γ, interleukin (IL)-1β, IL-2, IL-6, IL-8, IL-10, IL-17, tumor necrosis factor-α, soluble intercellular adhesion molecule-1, bone alkaline phosphatase, osteonectin, osteopontin) to extract factors associated with clinical remission (CDAI≤2.8) at 1 year using univariate analyses, and the extracted factors were entered into a multivariate logistic regression model. Similar analyses were also performed for Simplified Disease Activity Index (SDAI) remission (≤3.3) and Disease Activity Score with 28 joint counts, erythrocyte sedimentation rate (DAS28-ESR) remission (<2.6). Results There were no significant differences in the baseline characteristics except for methotrexate use between the groups. In the multivariate analyses, the low baseline osteopontin levels (OR 0.9145, 95% CI 0.8399–0.9857) were identified as predictors of CDAI remission in the tocilizumab group, whereas no predictors of CDAI remission were found in the infliximab group. Similar results were obtained when using SDAI and DAS28-ESR remission criteria. Conclusion Baseline low serum osteopontin levels predict clinical remission 1 year after tocilizumab treatment and not

  16. Follistatin-like protein 1 is elevated in systemic autoimmune diseases and correlated with disease activity in patients with rheumatoid arthritis

    PubMed Central

    2011-01-01

    Introduction Follistatin-like protein 1 (FSTL1) is a proinflammation mediator implicated in arthritis in rodent animal models. The present study is aimed at assessing FSTL1 levels in systemic autoimmune diseases and correlating them with disease activity in patients with rheumatoid arthritis (RA). Methods Serum FSTL1 levels from 487 patients with systemic autoimmune diseases and 69 healthy individuals were measured by enzyme-linked immunosorbent assay (ELISA). FSTL1 expression in synovial fluid (SF) and synovial tissues (STs) was determined by ELISA, immunohistochemistry, real-time polymerase chain reaction (RT-PCR) and western blot analysis in RA patients and trauma controls. FSTL1 levels in fibroblast-like synoviocytes (FLSs) from RA patients were determined by real-time PCR and western blot analysis. Results Serum FSTL1 levels were significantly elevated in patients with RA, ulcerative colitis, systemic lupus erythematosus, Sjögren's syndrome (SS), systemic sclerosis and polymyositis/dermatomyositis. Serum FSTL1 levels in the RA and secondary SS patients were substantially higher than those in other patients. Serum FSTL1 levels were increased in early RA, rheumatoid factor (RF)- and anti-cyclic citrullinated peptide antibody (ACPA)-negative patients compared to healthy controls. Moreover, serum FSTL1 concentrations were significantly higher in long-standing RA patients than in early RA patients and in the RF- and ACPA-positive RA patients than in RF- and ACPA-negative RA patients. Elevated FSTL1 levels in the STs and SF of RA patients were also observed. FSTL1 levels in serum were markedly higher than those in SF in RA patients. The strongest FSTL1 staining was detected in the cytoplasm of synovial and capillary endothelial cells from RA synovium. Furthermore, FSTL1 was induced in FLSs by inflammatory mediators. Importantly, serum FSTL1 levels were correlated with several important biologic and clinical markers of disease activity, including erythrocyte

  17. Sustained generation of nitric oxide and control of mycobacterial infection requires argininosuccinate synthase 1

    PubMed Central

    Qualls, Joseph E.; Subramanian, Chitra; Rafi, Wasiulla; Smith, Amber M.; Balouzian, Liza; DeFreitas, Ashley A.; Shirey, Kari Ann; Reutterer, Benjamin; Kernbauer, Elisabeth; Stockinger, Silvia; Decker, Thomas; Miyairi, Isao; Vogel, Stefanie N.; Salgame, Padmini; Rock, Charles O.; Murray, Peter J.

    2012-01-01

    Nitric oxide (NO) defends against intracellular pathogens but its synthesis must be regulated due to cell and tissue toxicity. During infection, macrophages import extracellular arginine to synthesize NO, generating the byproduct citrulline. Accumulated intracellular citrulline is thought to fuel arginine synthesis catalyzed by argininosuccinate synthase (Ass1) and argininosuccinate lyase (Asl), which would lead to abundant NO production. Instead, we find that citrulline is exported from macrophages during early stages of NO production with < 2% retained for recycling via the Ass1-Asl pathway. Later, extracellular arginine is depleted, and Ass1 expression allows macrophages to synthesize arginine from imported citrulline to sustain NO output. Ass1-deficient macrophages fail to salvage citrulline in arginine-scarce conditions, leading to their inability to control mycobacteria infection. Thus, extracellular arginine fuels rapid NO production in activated macrophages, and citrulline recycling via Ass1 and Asl is a fail-safe system that sustains optimum NO production. PMID:22980328

  18. Efavirenz does not cause false-positive urine cannabis test in HIV-infected patients on Highly Active Anti-Retroviral Therapy.

    PubMed

    Koh, K C; Lee, W Y; Eh, Z W; Nor Julaika, I; Tee, P S; Azizon, O; Thilageswary, M

    2013-06-01

    Efavirenz is a non-nucleoside reverse transcriptase inhibitor used in combination with other drugs for the treatment of patients with HIV infection. Efavirenz has been reported to cause a positive urine cannabis test reaction which may create problems between HIV-infected patients on Efavirenz and law enforcement agencies. Doctors are at loss whether to issue documents certifying the potential false positive urine cannabis test with Efavirenz to patients. We investigated if the urine of HIV-infected patients on Efavirenz caused a positive urine cannabis test using the AxSYM Cannabinoids Assay®. Urine samples from 51 eligible patients on Efavirenz were tested for cannabis. All tested negative except for one who had used cannabis the day before. Efavirenz does not cause false positive urine cannabis test with the AxSYM Cannabinoids Assay®. Certification documents from doctors are therefore unnecessary. PMID:23749016

  19. Adult sudden death caused by aspiration of chewing gum.

    PubMed

    Njau, S N

    2004-01-28

    A case of a fatal foreign material aspiration is presented in the following text. A 24-year-old white male died suddenly. A piece of chewing gum lodged in a pool of frothy fluid was revealed at autopsy. Microscopic examinations revealed atelectasia emphysema, eosinophilic exudate and empty spaces. Blood and urine samples were analyzed, for alcohol and drug use by fluorescence polarization immunoassay (FPIA) on an Abbott AXSYM system. No alcohol or other drugs were detected in blood or urine. PMID:15040903

  20. Misleading results from immunoassays of serum free thyroxine in the presence of rheumatoid factor.

    PubMed

    Norden, A G; Jackson, R A; Norden, L E; Griffin, A J; Barnes, M A; Little, J A

    1997-06-01

    A novel interference with measurements of serum free thyroxine (FT4) caused by rheumatoid factor (RhF) is described. We found misleading, sometimes gross, increases of FT4 results in 5 clinically euthyroid elderly female patients with high RhF concentrations. All 5 patients had high FT4 on Abbott AxSYM or IMx analyzers. "NETRIA" immunoassays gave misleading results in 4 of the 5 patients; Amerlex-MAB in 2 of 4 patients; AutoDELFIA in 2 of the 5; and Corning ACS-180 and Bayer Diagnostics Immuno 1 in 1 of the 5. BM-ES700 system results for FT4 in these women remained within the reference range. Results for serum T4, thyroid-stimulating hormone, free triiodothyronine, thyroid-hormone-binding globulin, and FT4 measured by equilibrium dialysis were normal in all 5 patients. Drugs, albumin-binding variants, and anti-thyroid-hormone antibodies were excluded as interferences. Addition to normal serum of the RhF isolated from each of the 5 patients increased the apparent FT4 (Abbott AxSYM). Screening of 83 unselected patients demonstrated a highly significant positive correlation between FT4 (Abbott AxSYM) and RhF concentrations. Discrepant, apparently increased FT4 with a normal result for thyroid-stimulating hormone should lead to measurement of the patient's RhF concentration. PMID:9191546

  1. Prevalence of Undiagnosed Diabetes in Rheumatoid Arthritis: an OGTT Study

    PubMed Central

    Ursini, Francesco; Russo, Emilio; D’Angelo, Salvatore; Arturi, Franco; Hribal, Marta Letizia; D’Antona, Lucia; Bruno, Caterina; Tripepi, Giovanni; Naty, Saverio; De Sarro, Giovambattista; Olivieri, Ignazio; Grembiale, Rosa Daniela

    2016-01-01

    Abstract Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by an excess of cardiovascular disease (CVD) risk, estimated to be at least 50% greater when compared to the general population. Although the widespread diffusion of type 2 diabetes mellitus (T2DM) awareness, there is still a significant proportion of patients with T2DM that remain undiagnosed. Aim of this cross-sectional study was to evaluate the prevalence of undiagnosed diabetes and prediabetes in RA patients. For the present study, 100 consecutive nondiabetic RA patients were recruited. Age- and sex-matched subjects with noninflammatory diseases (osteoarthritis or fibromyalgia) were used as controls. After overnight fasting, blood samples were obtained for laboratory evaluation including serum glucose, total cholesterol, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, triglycerides, uric acid, erythrocyte sedimentation rate (ESR), high sensitivity C-reactive protein (hs-CRP), rheumatoid factor (RF), and anti-Cyclic Citrullinated Peptide Antibodies (ACPA). A standard Oral Glucose Tolerance Test (OGTT) with 75 g of glucose was performed and blood samples were collected at time 0, 30, 60, 90, and 120 minutes, for measurement of plasma glucose concentrations. The prevalence of impaired fasting glucose (IFG) (9/100 vs 12/100, P = 0.49), impaired glucose tolerance (IGT) (19/100 vs 12/100, P = 0.17), and concomitant IFG/IGT (5/100 vs 9/100, P = 0.27) was similar between groups, whereas the prevalence of diabetes was significantly higher in RA patients (10/100 vs 2/100, P = 0.02). In a logistic regression analysis, increasing age (OR = 1.13, 95% CI 1.028–1.245, P = 0.01) and disease duration (OR = 1.90, 95% CI 1.210–2.995, P = 0.005) were both associated with an increased likelihood of being classified as prediabetes (i.e. IFG and/or IGT) or T2DM. A ROC curve was built to evaluate the predictivity of disease

  2. Watermelon, phytochemicals and health

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Watermelon fruit contains lycopene, a carotenoid pigment, and citrulline, an amino acid. These plant compounds may be helpful in preventing some chronic diseases. The amount of lycopene in watermelon ranges from 35 to 125 mg per kg of edible portion, and there is 2 to 4 mg per kg citrulline presen...

  3. Watermelon consumption increases plasma arginine concentrations in adults

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Watermelon is a good source of citrulline, an amino acid that can be converted to arginine in the human body. Arginine helps in cardiovascular and immune health. No studies have been conducted to evaluate plasma arginine response in humans following consumption of citrulline from natural plant so...

  4. Arginine production in the neonate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Endogenous arginine synthesis in adults is a complex multiorgan process, in which citrulline is synthesized in the gut, enters the general circulation, and is converted into arginine in the kidney, by what is known as the intestinal-renal axis. In neonates, the enzymes required to convert citrulline...

  5. PAD4 mediated histone hypercitrullination induces heterochromatin decondensation and chromatin unfolding to form neutrophil extracellular trap-like structures

    PubMed Central

    Leshner, Marc; Wang, Shu; Lewis, Carrie; Zheng, Han; Chen, Xiangyun Amy; Santy, Lorraine; Wang, Yanming

    2012-01-01

    NETosis, the process wherein neutrophils release highly decondensed chromatin called neutrophil extracellular traps (NETs), has gained much attention as an alternative means of killing bacteria. In vivo, NETs are induced by bacteria and pro-inflammatory cytokines. We have reported that peptidylarginine deiminase 4 (PAD4), an enzyme that converts Arg or monomethyl-Arg to citrulline in histones, is essential for NET formation. The areas of extensive chromatin decondensation along the NETs were rich in histone citrullination. Here, upon investigating the effect of global citrullination in cultured cells, we discovered that PAD4 overexpression in osteosarcoma U2OS cells induces extensive chromatin decondensation independent of apoptosis. The highly decondensed chromatin is released to the extracellular space and stained strongly by a histone citrulline-specific antibody. The structure of the decondensed chromatin is reminiscent of NETs but is unique in that it occurs without stimulation of cells with pro-inflammatory cytokines and bacteria. Furthermore, histone citrullination during chromatin decondensation can dissociate heterochromatin protein 1 beta (HP1β) thereby offering a new molecular mechanism for understanding how citrullination regulates chromatin function. Taken together, our study suggests that PAD4 mediated citrullination induces chromatin decondensation, implicating its essential role in NET formation under physiological conditions in neutrophils. PMID:23060885

  6. Glutathione-supported arsenate reduction coupled to arsenolysis catalyzed by ornithine carbamoyl transferase

    SciTech Connect

    Nemeti, Balazs; Gregus, Zoltan

    2009-09-01

    Three cytosolic phosphorolytic/arsenolytic enzymes, (purine nucleoside phosphorylase [PNP], glycogen phosphorylase, glyceraldehyde-3-phosphate dehydrogenase) have been shown to mediate reduction of arsenate (AsV) to the more toxic arsenite (AsIII) in a thiol-dependent manner. With unknown mechanism, hepatic mitochondria also reduce AsV. Mitochondria possess ornithine carbamoyl transferase (OCT), which catalyzes phosphorolytic or arsenolytic citrulline cleavage; therefore, we examined if mitochondrial OCT facilitated AsV reduction in presence of glutathione. Isolated rat liver mitochondria were incubated with AsV, and AsIII formed was quantified. Glutathione-supplemented permeabilized or solubilized mitochondria reduced AsV. Citrulline (substrate for OCT-catalyzed arsenolysis) increased AsV reduction. The citrulline-stimulated AsV reduction was abolished by ornithine (OCT substrate inhibiting citrulline cleavage), phosphate (OCT substrate competing with AsV), and the OCT inhibitor norvaline or PALO, indicating that AsV reduction is coupled to OCT-catalyzed arsenolysis of citrulline. Corroborating this conclusion, purified bacterial OCT mediated AsV reduction in presence of citrulline and glutathione with similar responsiveness to these agents. In contrast, AsIII formation by intact mitochondria was unaffected by PALO and slightly stimulated by citrulline, ornithine, and norvaline, suggesting minimal role for OCT in AsV reduction in intact mitochondria. In addition to OCT, mitochondrial PNP can also mediate AsIII formation; however, its role in AsV reduction appears severely limited by purine nucleoside supply. Collectively, mitochondrial and bacterial OCT promote glutathione-dependent AsV reduction with coupled arsenolysis of citrulline, supporting the hypothesis that AsV reduction is mediated by phosphorolytic/arsenolytic enzymes. Nevertheless, because citrulline cleavage is disfavored physiologically, OCT may have little role in AsV reduction in vivo.

  7. Erythropoiesis: Short Report: Translation of Analysis Results between Serum Ferritin Assays, Ferritin RIA AmershamTM and Abbott AxSYMTM Ferritin.

    PubMed

    Milman, NILS; Byg, KELD-ERIK; Juul-Jørgensen, BIRGIT; Weis Bentzon, MICHAEL

    1999-01-01

    The serum ferritin assays, Ferritin RIA Amersham(TM) and Abbott AxSYM(TM) Ferritin were compared in order to translate values from one assay to the other. Serum ferritin was analysed with both assays in 102 samples. Logarithmic transformation of the results was performed in order to stabilize the variance. The relationship between the untransformed values was most exactly expressed by a proportionality: AxSYM Ferritin = 0.873 * RIA Ferritin. Due to this proportionality, the numerical difference between the assays increases with the ferritin concentration, although the percentage difference between the assays remains constant. PMID:11399562

  8. Scanning genomic areas under selection sweep and association mapping as tools to identify horticultural important genes in watermelon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Watermelon (Citrullus lanatus var. lanatus) contains 88% water, sugars, and several important health-related compounds, including lycopene, citrulline, arginine, and glutathione. The current genetic diversity study uses microsatellites with known map positions to identify genomic regions that under...

  9. Important roles for the arginine family of amino acids in swine nutrition and production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arginine, glutamine, glutamate, proline, aspartate, asparagine, ornithine, and citrulline are interconvertible via complex interorgan metabolism in most mammals (including the pig). The major sites for their metabolism are the small intestine, kidneys, and liver, with cortisol being a key regulatory...

  10. Characterization of the Hypercitrullination Reaction in Human Neutrophils and Other Leukocytes

    PubMed Central

    Zhou, Yebin; Di Pucchio, Tiziana; Sims, Gary P.; Mittereder, Nanette; Mustelin, Tomas

    2015-01-01

    Autoantibodies against citrullinated proteins are diagnostic for rheumatoid arthritis. However, the molecular mechanisms driving protein citrullination in patients with rheumatoid arthritis remain poorly understood. Using two independent western blotting methods, we report that agents that trigger a sufficiently large influx of extracellular calcium ions induced a marked citrullination of multiple proteins in human neutrophils, monocytes, and, to a lesser extent, T lymphocytes and natural killer cells, but not B lymphocytes or dendritic cells. This response required 250–1,000 μM extracellular calcium and was prevented by EDTA. Other neutrophil activating stimuli, such as formyl-peptides, GM-CSF, IL-6, IL8, TNFα, or phorbol ester, did not induce any detectable increase in protein citrullination, suggesting that receptor-induced calcium mobilization is insufficient to trigger hypercitrullination. We conclude that loss of membrane integrity and subsequent influx of high levels of calcium, which can be triggered by perforin released from cytotoxic cells or complement mediated formation of membrane attack complexes in the joints of rheumatoid arthritis patients, are sufficient to induce extensive protein citrullination in immune cells, notably neutrophils. This mechanism may provide the citrullinated autoantigens that drive autoimmunity in this devastating disease. PMID:26078491