Arthritis Phenotypes Research Articles

ATP triggers a robust intracellular [Ca2+ ]-mediated signalling pathway in human synovial fibroblasts.

What is the central question of this study? What are the main [Ca2+ ]i signalling pathways activated by ATP in human synovial fibroblasts? What is the main finding and its importance? In human synovial fibroblasts ATP acts through a linked G-protein (Gq ) and phospholipase C signalling mechanism to produce IP3 , which then markedly enhances release of Ca2+ from the endoplasmic reticulum. These results provide new information for the detection of early pathophysiology of arthritis. In human articular joints, synovial fibroblasts (HSFs) have essential physiological functions that include synthesis and secretion of components of the extracellular matrix and essential articular joint lubricants, as well as release of paracrine substances such as ATP. Although the molecular and cellular processes that lead to a rheumatoid arthritis (RA) phenotype are not fully understood, HSF cells exhibit significant changes during this disease progression. The effects of ATP on HSFs were studied by monitoring changes in intracellular Ca2+ ([Ca2+ ]i ), and measuring electrophysiological properties. ATP application to HSF cell populations that had been enzymatically released from 2-D cell culture revealed that ATP (10-100μm), or its analogues UTP or ADP, consistently produced a large transient increase in [Ca2+ ]i . These changes (i) were initiated by activation of the P2 Y purinergic receptor family, (ii) required Gq -mediated signal transduction, (iii) did not involve a transmembrane Ca2+ influx, but instead (iv) arose almost entirely from activation of endoplasmic reticulum (ER)-localized inositol 1,4,5-trisphosphate (IP3 ) receptors that triggered Ca2+ release from the ER. Corresponding single cell electrophysiological studies revealed that these ATP effects (i) were insensitive to [Ca2+ ]o removal, (ii) involved an IP3 -mediated intracellular Ca2+ release process, and (iii) strongly turned on Ca2+ -activated K+ current(s) that significantly hyperpolarized these cells. Application of histamine produced very similar effects in these HSF cells. Since ATP is a known paracrine agonist and histamine is released early in the inflammatory response, these findings may contribute to identification of early steps/defects in the initiation and progression of RA.

Ustekinumab in psoriatic arthritis and related phenotypes.

Psoriatic arthritis (PsA) is an inflammatory arthritis that commonly occurs with psoriasis and is attributed to genetic, immunologic and environmental factors. The T-helper (Th)-17 pathway and the interleukin (IL)-23/IL-17 axis have become prominent players in PsA and considerably increased our understanding of disease pathogenesis. In this review article, we will focus on the emerging role of IL-12/23 and its blockade, in the pathogenesis and management of PsA as well as of psoriasis and inflammatory bowel disease. Ustekinumab, is a fully human monoclonal immunoglobulin (Ig)G1 antibody that binds specifically to the p40 subunit of IL-12 and IL-23, primarily inhibiting downstream Th-17 signalling pathways. Ustekinumab produced consistent and sustained clinical efficacy in two phase III clinical trials in PsA, PSUMMIT-1 and PSUMMIT-2, with data out to 52 weeks, and no new safety signals. PSUMMIT-1 included patients with active PsA despite conventional therapy who were all naïve to anti-tumour necrosis factor (TNF) agents, whereas PSUMMIT-2 also included anti-TNF experienced patients. Similarly, ustekinumab produced consistent clinical efficacy in two phase III clinical trials in psoriasis, PHOENIX-1 and PHOENIX-2, and in both induction and maintenance of moderate-to-severe Crohn's disease, UNITI-1, UNITI-2 and IM-UNITI, without an increased safety signal. Currently, ustekinumab is used in the treatment of PsA following the failure of nonsteroidal anti-inflammatory drugs (NSAIDs) and conventional disease-modifying antirheumatic drugs (DMARDs), and as an alternative to, or after failure of an anti-TNF agent.

244 The clinical phenotype of inflammatory arthritis correlates with synovial immune cell infiltration: results from the pathobiology of early arthritis cohort

244 The clinical phenotype of inflammatory arthritis correlates with synovial immune cell infiltration: results from the pathobiology of early arthritis cohort

Role of TNF-Alpha and IL10 genes in the development and clinical manifestations of psoriatic arthritis

ObjectiveTo evaluate the impact of polymorphisms of TNF-alpha (TNFA) and IL10 genes and their association with clinical phenotypes of psoriatic arthritis (PsA). Materials and methodsThe study included 104 unrelated Venezuelan individuals, grouped into 52 patients with PsA, who fulfilled the CASPAR criteria, and 52 healthy individuals with no family history of psoriasis. The polymorphisms of the TNFA and IL10 genes were determined by Single Specific Primer-Polymerase Chain Reaction (SSP-PCR). ResultsThe GA genotype and A allele of the TNFA-238G/A polymorphism appears to confer protection against the development of PsA (OR: 0.31, 95% CI: 0.92–1.05, p=0.02). The GA genotype of the TNFA-308G/A polymorphism is associated with a late onset age of PsA (GA=60±13.17 years vs. GG=43.55±14.29 years, p=0.002), and the GG genotype of the IL10 -1082A/G polymorphism with a longer time interval between the onset of psoriasis and the development of PsA (GG=27.4±24.11 years, GA=5.47±7.23 years, AA=7.86±8.51 years, p=0.001). The CC genotypes of IL10-819 C/T and IL10-592 C/A confer risk of damage to distal interphalangeal joints (OR: 4.79, p=0.026). ConclusionsThe TNFA-238G/A polymorphism plays an important role in the development of PsA in mixed-race Venezuelans. Likewise, TNFA-308 G/A, IL10 -1082 A/G, -819C/T, -592C/A polymorphisms may modify the clinical expression of PsA.

Papel de los genes TNFA e IL10 en el desarrollo y manifestaciones clínicas de la artritis psoriásica

ObjectiveTo evaluate the impact of polymorphisms of TNF-alpha (TNFA) and IL10 genes and their association with clinical phenotypes of psoriatic arthritis (PsA). Materials and methodsThe study included 104 unrelated Venezuelan individuals, grouped into 52 patients with PsA, who fulfilled the CASPAR criteria, and 52 healthy individuals with no family history of psoriasis. The polymorphisms of the TNFA and IL10 genes were determined by Single Specific Primer-Polymerase Chain Reaction (SSP-PCR). ResultsThe GA genotype and A allele of the TNFA-238G/A polymorphism appears to confer protection against the development of PsA (OR: 0.31, 95% CI: 0.92 -1.05, P=.02). The GA genotype of the TNFA-308G/A polymorphism is associated with a late onset age of PsA (GA=60±13.17 years vs. GG=43.55±14.29 years, P=.002), and the GG genotype of the IL10 -1082A/G polymorphism with a longer time interval between the onset of psoriasis and the development of PsA (GG=27.4±24.11 years, GA=5.47±7.23 years, AA=7.86±8.51 years, P=.001). The CC genotypes of IL10-819C/T and IL10-592C/A confers risk of damage to distal interphalangeal joints (OR: 4.79, P=.026) ConclusionsThe TNFA-238G/A polymorphism plays an important role in the development of PsA in mixed-race Venezuelans. Likewise, TNFA-308 G/A, IL10 -1082 A/G, -819C/T, -592C/A polymorphisms may modify the clinical expression of PsA.

Association Between Menopausal Factors and the Risk of Seronegative and Seropositive Rheumatoid Arthritis: Results From the Nurses’ Health Studies

To investigate whether menopausal factors are associated with the development of serologic rheumatoid arthritis (RA) phenotypes. Data were analyzed from the Nurses' Health Studies (NHS; 1976-2010 and NHSII 1989-2011). A total of 120,700 female nurses ages 30-55 years in the NHS, and a total of 116,430 female nurses ages 25-42 years in the NHSII, were followed via biennial questionnaires on lifestyle and disease outcomes. In total, 1,096 incident RA cases were confirmed by questionnaire and chart review. Seropositive RA was defined as rheumatoid factor positive (RF) or antibodies to citrullinated protein antigen (ACPA) positive, and seronegative RA was defined as RF negative and ACPA negative. We used Cox proportional hazards models to obtain multivariable-adjusted hazard ratios (HRs) with 95% confidence intervals (95% CIs) of seropositive/seronegative RA associated with menopausal status, age at menopause, type of menopause, ovulatory years, and postmenopausal hormone therapy (PMH) use. Postmenopausal women had a 2-fold increased risk of seronegative RA, compared with premenopausal women (NHS: HR 1.8 [95% CI 1.1-3.0], NHSII: HR 2.4 [95% CI 1.4-3.9], and pooled HR 2.1 [95% CI 1.4-3.0]). Natural menopause at early age (≤44 years) was associated with an increased risk of seronegative RA (pooled HR 2.4 [95% CI 1.5-4.0]). None of the menopausal factors was significantly associated with seropositive RA. We observed no association between PMH use and the risk of seronegative or seropositive RA, except that PMH use of ≥8 years was associated with increased risk of seropositive RA (pooled HR 1.4 [95% CI 1.1-1.9]). Postmenopause and natural menopause at an early age were strongly associated with seronegative RA, but only marginally with seropositive RA, suggesting potential differences in the etiology of RA subtypes.

Aberrant intestinal microbiota due to IL-1 receptor antagonist deficiency promotes IL-17- and TLR4-dependent arthritis

BackgroundPerturbation of commensal intestinal microbiota has been associated with several autoimmune diseases. Mice deficient in interleukin-1 receptor antagonist (Il1rn−/− mice) spontaneously develop autoimmune arthritis and are susceptible to other autoimmune diseases such as psoriasis, diabetes, and encephalomyelitis; however, the mechanisms of increased susceptibility to these autoimmune phenotypes are poorly understood. We investigated the role of interleukin-1 receptor antagonist (IL-1Ra) in regulation of commensal intestinal microbiota, and assessed the involvement of microbiota subsets and innate and adaptive mucosal immune responses that underlie the development of spontaneous arthritis in Il1rn−/− mice.ResultsUsing high-throughput 16S rRNA gene sequencing, we show that IL-1Ra critically maintains the diversity and regulates the composition of intestinal microbiota in mice. IL-1Ra deficiency reduced the intestinal microbial diversity and richness, and caused specific taxonomic alterations characterized by overrepresented Helicobacter and underrepresented Ruminococcus and Prevotella. Notably, the aberrant intestinal microbiota in IL1rn−/− mice specifically potentiated IL-17 production by intestinal lamina propria (LP) lymphocytes and skewed the LP T cell balance in favor of T helper 17 (Th17) cells, an effect transferable to WT mice by fecal microbiota. Importantly, LP Th17 cell expansion and the development of spontaneous autoimmune arthritis in IL1rn−/− mice were attenuated under germ-free condition. Selective antibiotic treatment revealed that tobramycin-induced alterations of commensal intestinal microbiota, i.e., reduced Helicobacter, Flexispira, Clostridium, and Dehalobacterium, suppressed arthritis in IL1rn−/− mice. The arthritis phenotype in IL1rn−/− mice was previously shown to depend on Toll-like receptor 4 (TLR4). Using the ablation of both IL-1Ra and TLR4, we here show that the aberrations in the IL1rn−/− microbiota are partly TLR4-dependent. We further identify a role for TLR4 activation in the intestinal lamina propria production of IL-17 and cytokines involved in Th17 differentiation preceding the onset of arthritis.ConclusionsThese findings identify a critical role for IL1Ra in maintaining the natural diversity and composition of intestinal microbiota, and suggest a role for TLR4 in mucosal Th17 cell induction associated with the development of autoimmune disease in mice.

Anticollagen type II antibodies are associated with an acute onset rheumatoid arthritis phenotype and prognosticate lower degree of inflammation during 5 years follow-up.

ObjectiveAntifibrillar collagen type II (anti-CII) antibody-positive patients with rheumatoid arthritis (RA) have early but not late signs of increased inflammation and joint erosions. We wanted to replicate this in a large RA cohort, and to relate to human leukocyte antigen (HLA)-DRB1* alleles.MethodsAnti-CII and anti-cyclic citrullinated peptide (CCP)2 were measured at baseline in 773 patients with RA from the Swedish Epidemiological Investigation in Rheumatoid Arthritis (EIRA) study with clinical follow-up data from the Swedish Rheumatology Quality Register (SRQ) registry, and 1476 with HLA-DRB1* information. Comparisons were done concerning C reactive protein (CRP), erythrocyte sedimentation rate (ESR), tender joint count (TJC), swollen joint count (SJC), Disease Activity Score encompassing 28 joints based on ESR (DAS28), DAS28CRP, pain-Visual Analogue Scale (VAS), global-VAS and Health Assessment Questionnaire Score (HAQ) at eight occasions during 5 years, and association with HLA-DRB1* alleles.ResultsAnti-CII associated with elevated CRP, ESR, SJC, DAS28 and DAS28CRP at diagnosis and up to 6 months, whereas anti-CCP2 associated with SJC and DAS28 from 6 months to 5 years, but not earlier. The anti-CII-associated phenotype was strong, and predominated in anti-CII/anti-CCP2 double-positive patients. Anti-CII was associated with improvements in CRP, ESR, SJC, TJC and DAS28, whereas anti-CCP2 was associated with deteriorations in SJC and DAS28 over time. Anti-CII-positive patients achieved European League Against Rheumatism good or moderate response more often than negative patients. Anti-CII was positively associated with HLA-DRB1*01 and HLA-DRB1*03, with significant interaction, and double-positive individuals had >14 times higher mean anti-CII levels than HLA double negatives. Whereas smoking was associated with elevated anti-CCP2 levels, smokers had lower anti-CII levels.ConclusionsAnti-CII seropositive RA represents a distinct phenotype, in many respects representing the converse to the clinical, genetic and smoking associations described for anticitrullinated protein peptide autoantibodies. Although not diagnostically useful, early anti-CII determinations predict favourable inflammatory outcome in RA.

CD11b regulates the Treg/Th17 balance in murine arthritis via IL-6.

Th17 cells are often associated with autoimmunity and been shown to be increased in CD11b-/- mice. Here, we examined the role of CD11b in murine collagen-induced arthritis (CIA). C57BL/6 and CD11b-/- resistant mice were immunized with type II collagen. CD11b-/- mice developed arthritis with early onset, high incidence, and sustained severity compared with C57BL/6 mice. We observed a marked leukocyte infiltration, and histological examinations of the arthritic paws from CD11b-/- mice revealed that the cartilage was destroyed in association with strong lymphocytic infiltration. The CD11b deficiency led to enhanced Th17-cell differentiation. CD11b-/- dendritic cells (DCs) induced much stronger IL-6 production and hence Th17-cell differentiation than wild-type DCs. Treatment of CD11b-/- mice after establishment of the Treg/Th17 balance with an anti-IL-6 receptor mAb significantly suppressed the induction of Th17 cells and reduced arthritis severity. Finally, the severe phenotype of arthritis in CD11b-/- mice was rescued by adoptive transfer of CD11b+ DCs. Taken together, our results indicate that the resistance to CIA in C57BL/6 mice is regulated by CD11b via suppression of IL-6 production leading to reduced Th17-cell differentiation. Therefore, CD11b may represent a susceptibility factor for autoimmunity and could be a target for future therapy.

Rheumatoid arthritis phenotype at presentation differs depending on the number of autoantibodies present

ObjectivesIn rheumatoid arthritis (RA), seropositive and seronegative disease may be two entities with different underlying pathophysiological mechanisms, long-term outcomes and disease presentations. However, the effect of the conjoint presence of...

Loss of the longevity gene SirT1 dysregulates chondrocytes and leads to an arthritic phenotype in vivo, via impaired autophagy

Searchable abstracts of presentations at key conferences on calcified tissues ISSN 2052-1219 (online)

Su1832 Sacroiliitis is underrecognized in Inflammatory Bowel Disease and is Associated With Previous Arthritis and Inflammatory Crohn's Phenotype

Su1832 Sacroiliitis is underrecognized in Inflammatory Bowel Disease and is Associated With Previous Arthritis and Inflammatory Crohn's Phenotype

The role of KIR2DL3/HLA-C*0802 in Brazilian patients with rheumatoid vasculitis

OBJECTIVES:Rheumatoid arthritis is a polygenically controlled systemic autoimmune disease. Rheumatoid vasculitis is an important extra-articular phenotype of rheumatoid arthritis that can result in deep cutaneous ulcers. The objective of this study was to establish a correlation between the frequency of major histocompatibility complex class I/II alleles and killer immunoglobulin-like receptor genotypes in patients with cutaneous rheumatoid vasculitis.METHODS:Using the Scott & Bacon 1984 criteria to diagnose rheumatoid vasculitis and after excluding any other causes such as diabetes, atherosclerosis, adverse drug reactions, infection, and smoking, patients who met the criteria were selected. All of the selected rheumatoid vasculitis patients presented deep cutaneous ulcers. Identification of the major histocompatibility complex class I/II and killer immunoglobulin-like receptor genotypes was performed by polymerase chain reaction assays of samples collected from the 23 rheumatoid vasculitis patients as well as from 80 controls (40 non-rheumatoid vasculitis RA control patients and 40 healthy volunteers).RESULTS:An association between the presence of the HLA-DRB1*1402 and HLA-DRB1*0101 alleles and cutaneous lesions in rheumatoid vasculitis patients and a correlation between the inhibitor KIR2DL3 and the HLA-C*0802 ligand in rheumatoid vasculitis patients were found.CONCLUSION:An association was found between the presence of the HLA-DRB1*1402 and HLA-DRB1*0101 alleles and the development of cutaneous lesions in rheumatoid vasculitis patients. Additionally, the HLA-C*0802 ligand protects these individuals from developing cutaneous lesions.

Association analysis of copy numbers of FC-gamma receptor genes for rheumatoid arthritis and other immune-mediated phenotypes.

Segmental duplications (SDs) comprise about 5% of the human genome and are enriched for immune genes. SD loci often show copy numbers variations (CNV), which are difficult to tag with genotyping methods. CNV in the Fcγ receptor region (FCGR) has been suggested to be associated with rheumatic diseases. The objective of this study was to delineate association of FCGR-CNV with rheumatoid arthritis (RA), coeliac disease and Inflammatory bowel disease incidence. We developed a method to accurately quantify CNV in SD loci based on the intensity values from the Immunochip platform and applied it to the FCGR locus. We determined the method's validity using three independent assays: segregation analysis in families, arrayCGH, and whole genome sequencing. Our data showed the presence of two separate CNVs in the FCGR locus. The first region encodes FCGR2A, FCGR3A and part of FCGR2C gene, the second encodes another part of FCGR2C, FCGR3B and FCGR2B. Analysis of CNV status in 4578 individuals with RA and 5457 controls indicated association of duplications in the FCGR3B gene in antibody-negative RA (P=0.002, OR=1.43). Deletion in FCGR3B was associated with increased risk of antibody-positive RA, consistently with previous reports (P=0.023, OR=1.23). A clear genotype-phenotype relationship was observed: CNV polymorphisms of the FCGR3A gene correlated to CD16A expression (encoded by FCGR3A) on CD8 T-cells. In conclusion, our method allows determining the CNV status of the FCGR locus, we identified association of CNV in FCGR3B to RA and showed a functional relationship between CNV in the FCGR3A gene and CD16A expression.

Brief Report: Tumor Necrosis Factor and Interleukin‐6 Differentially Regulate Dkk‐1 in the Inflamed Arthritic Joint

ObjectiveTumor necrosis factor (TNF) drives bone destruction, but it also inhibits new bone formation by inducing Dkk‐1, an inhibitor of the Wnt pathway. Accordingly, blocking of Dkk‐1 reverses the phenotype in experimental arthritis from a pattern of bone destruction to a pattern of bone formation. To delineate the potential role of Dkk‐1 in the structural phenotype of human arthritis, we analyzed the expression of Dkk‐1 and its regulation by proinflammatory cytokines in the inflamed peripheral joints of patients with spondyloarthritis (SpA) and rheumatoid arthritis (RA).MethodsExpression of Dkk‐1 and proinflammatory cytokines was determined by enzyme‐linked immunosorbent assay and microarray analysis in synovial fluid (SF) and synovial tissue, respectively. Regulation of Dkk‐1 production by proinflammatory cytokines was assessed in fibroblast‐like synoviocyte (FLS) cultures.ResultsTNF and interleukin‐1β (IL‐1β) levels, were higher in RA SF than in SpA SF (P < 0.001 for both), whereas levels of IL‐6 were not. Levels of Dkk‐1 were similar in SpA SF and RA SF and were not correlated with TNF and IL‐1β levels. However, Dkk‐1 levels showed an inverse correlation with IL‐6 levels in both SpA SF (r = −0.31, P = 0.04) and RA SF (r = −0.39, P = 0.01); this result was reproduced at the messenger RNA level in synovial tissue. In vitro experiments with FLS confirmed that Dkk‐1 production was strongly induced by TNF but clearly suppressed by IL‐6. Moreover, IL‐6 was able to suppress the TNF‐induced up‐regulation of Dkk‐1 production by FLS.ConclusionThe inverse correlation of Dkk‐1 levels with IL‐6 levels observed in vivo in the inflamed joints was mirrored by the differential regulation of Dkk‐1 production by TNF and IL‐6 in vitro. The relative balance between these and other factors in the arthritic joints may determine functional Wnt signaling and tissue remodeling.

Targeting CD226/DNAX accessory molecule-1 (DNAM-1) in collagen-induced arthritis mouse models.

BackgroundGenetic studies have pointed out that CD226 variants, encoding DNAM-1, could be associated with susceptibility to rheumatoid arthritis. Therefore, we aimed to determine the influence of DNAM-1 on the development of arthritis using the collagen-induced arthritis (CIA) mouse model.MethodsCIA was induced in mice on a DBA/1 background, treated in parallel with a DNAM-1 neutralizing monoclonal antibody, a control IgG and PBS, respectively. CIA was also induced in mice deficient for DNAM-1(dnam1−/−) and control dnam-1+/+ mice on a C57/BL6 background. Mice were monitored for clinical and ultrasound signs of arthritis. Histological analysis was performed to search for inflammatory infiltrates and erosions. The Mann–Whitney U test for non-related samples was used for statistical analysis.ResultsThere was a non-significant trend for a less arthritic phenotype in mice receiving anti-DNAM-1 mAb at both clinical, ultrasound and histological assessments. But, we did not observe any difference between dnam1+/+ and dnam1−/− mice for incidence nor severity of clinical arthritis. Histological analysis revealed inflammatory scores similar in both groups, without evidence of erosion. Collagen antibodies levels were similar in all mice, confirming immunization with collagen.ConclusionDespite some clues suggesting a role of DNAM-1 in arthritis, these complementary approaches demonstrate no contribution of CD226/DNAM-1 in the arthritic phenotype. These results contrast with previous studies showing a role in vivo of DNAM-1 in some autoimmune disorders.Electronic supplementary materialThe online version of this article (doi:10.1186/s12950-015-0056-5) contains supplementary material, which is available to authorized users.

Certain class I HLA alleles and haplotypes implicated in susceptibility play a role in determining specific features of the psoriatic arthritis phenotype

ObjectivesPsoriatic arthritis (PsA) susceptibility is associated with several different class I alleles, suggesting separate patterns of MHC effect. This exploratory study was based on the hypothesis that heterogeneity of the...

FRI0358 Contribution of the Adhesion Receptor DNAX Accessory Molecule-1 (DNAM-1) in the Development of Experimental Arthritis

BackgroundRheumatoid arthritis (RA) is a frequent disease leading to joint destruction, deformity, and loss of function. Its pathogenesis results from the combination of genetic susceptibility genes and environmental factors. Recently,...

OP0100 Indoleamine 2,3 Dioxygenase I Expression in Sjogren's Sialoadenitis Correlates with the Local Amount of B-Lymphocytes and Plasmocytoid Dendritic Cells

BackgroundIndoleamine 2,3 dioxygenase 1 and 2 (IDO1-IDO2) enzymes catabolise tryptophan (TR) to its metabolite kyurenine (KNR), and are competitively inhibited by 1-Methyl-TR (1M-TR). IDO1-IDO2, once activated in dendritic cells (DCs)...

AB0880 Farber Disease Diagnosed as Juvenile Idiopathic Arthritis

BackgroundFarber lipogranulomatosis (Farber Disease; FD) is an ultra-rare lysosomal storage disorder resulting from the inherited deficiency of the enzyme acid ceramidase, and the accumulation of the lipid substrate ceramide. Ceramide...