GPR15 expressed in T lymphocytes from RA patients is involved in leukocyte chemotaxis to the synovium.

The rheumatoid arthritis (RA) inflammatory process occurs in the joints where immune cells are attracted into the synovium to promote remodeling and tissue damage. GPR15 is a G protein-coupled receptor (GPCR) located on chromosome 3 and has similarity in its sequence with chemokine receptors. Recent evidence indicates that GPR15 may be associated with modulation of the chronic inflammatory response. We evaluated the expression of GPR15 and GPR15L in blood and synovial tissue samples from RA patients, as well as to perform a functional migration assay in response to GPR15L. The expression of GPR15 and c10orf99/gpr15l mRNA was analyzed by RT-qPCR. Samples of synovial fluid and peripheral blood were analyzed for CD45+CD3+CD4+GPR15+ and CD45+CD3+CD8+GPR15+ T cell frequency comparing RA patients versus control subjects by flow cytometry. Migration assays were performed using PBMCs isolated from these individuals in response to the synthetic GPR15 ligand. Statistical analysis included Kruskal-Wallis test, T-test, or Mann-Whitney U test, according to data distribution. A higher expression in the mRNA for GPR15 was identified in early RA subjects. The frequencies of CD4+/CD8+ GPR15+ T lymphocytes are higher in RA patients comparing with healthy subjects. Also, the frequency CD4+/CD8+ GPR15+ T lymphocytes are higher in synovial fluid of established RA patients comparing with OA patients. GPR15 and GPR15L are present in the synovial tissue of RA patients and GPR15L promotes migration of PBMCs from RA patients and healthy subjects. Our results suggest that GPR15/GPR15L have a pathogenic role in RA and their antagonizing could be a therapeutic approach in RA.

Overexpression of TLR7 and TLR9 Occurs Before Onset Symptoms In First-Degree Relatives of Rheumatoid Arthritis Patients.

BACKGROUND: Autoantibodies have a central role in the physiopathology of Rheumatoid Arthritis (RA). However, the responsible factors that trigger and perpetuate the autoantibodies production are unknown. Toll-like receptors (TLRs) have been considered as promotors of autoantibodies production to break down the immunotolerance in RA. AIM OF THE STUDY: Evaluate the expression levels of TLR7 and TLR9 as well as their correlation with autoantibodies in first-degree relatives (FDR) of RA patients (seropositive and seronegative to ACPA), respect to early RA (eRA) and chronic RA (cRA) patients. METHODS: We selected 32 RA patients (16 as eRA and 16 as cRA) and 32 FDR of RA patients (16 seropositive and 16 seronegative to ACPA). Expression levels of TLR7 and TLR9 in whole blood samples from each group were measured by real-time PCR using total RNA extracted from each subject. Also, correlation analysis between TLRs expression and autoantibodies was performed. RESULTS: The expression of TLR7 and TLR9 was diminished in RA patients (p <0.01) but elevated in ACPA- FDR (p <0.0001) and ACPA+ FDR (p <0.05) with a positive correlation between them (r = 0.749, p <0.000). Moreover, the expression levels of TLR7 correlate positively with ACPA levels in both seropositive ACPA+ FDR subjects (r = 0.582, p = 0.018) and eRA patients (r = 0.593, p = 0.020). CONCLUSIONS: Our results showed overexpression of TLR7 and TLR9 may occur in preclinical RA subjects. TLR7 overexpression correlated with ACPA levels' production, suggesting TLR7 may play a role in ACPA development.

Calpain Participates in Cortical Cytoskeleton Modification and DNA Release during Neutrophil Extracellular Trap Formation.

INTRODUCTION: The formation of neutrophil extracellular traps (NETs) is a process in which several kinds of enzymes participate generating posttranslational modifications of proteins. NETs have been associated with infectious, autoimmune, and inflammatory diseases. Inhibition of several proteases reduces the formation of NETs. In the present work, we analyzed the role of several broad-acting and specific inhibitors of proteases in the formation of NETs. METHODS: Neutrophils were isolated from peripheral blood of healthy individuals by density gradient. The neutrophils were quantified and seeded into cell culture plates. Phorbol myristate acetate and A23187 were used as NETs inducers, and several specific inhibitors of proteases were used. The cells were stained for cytoskeleton or DNA. The cell-free supernatants were used to assess DNA release. Statistical analysis was carried out by a Kruskal-Wallis or ANOVA test. RESULTS: We observed marked changes in actin organization after the induction of NETs, suggesting that the cytoskeleton is being actively regulated. When we used protease inhibitors, the release of DNA was reduced, suggesting the participation of actin remodeling in the process. Further characterization of the specific proteases revealed that calpain modulates the reorganization of actin cytoskeleton and DNA release. Preservation of part of the actin cytoskeleton suggests that DNA release is not only a mechanic process associated to the chromatin decondensation; rather the process is highly regulated by active proteases that promote cytoskeleton reorganization and chromatin decondensation that culminates in DNA release. CONCLUSION: Calpain mediates the DNA release in the NET formation process by the modification of cortical actin cytoskeleton in a calcium-dependent manner.

Methotrexate reduces keratinocyte proliferation, migration and induces apoptosis in HaCaT keratinocytes in vitro and reduces wound closure in Skh1 mice in vivo.

The aim of the present work was to evaluate MTX treatment (0.1, 1 and 10 µg mL-1) in vitro in order to characterize its effects on cell proliferation alterations in cell cycle of HaCaT keratinocytes and wound healing in a Skh1 mice treated with MTX (low doses 30 mg kg-1, high doses 200 mg kg-1 and repeated doses at 1.5 mg kg-1). We analyzed the cytotoxic effect of methotrexate by a resazurin assay. The effects in the proliferation, cell cycle and apoptosis of HaCaT cells were analyzed by flow cytometry. The effects of MTX on wound healing in vivo were also analyzed. A trend toward reduction in the resazurin assay was found (p > 0.05). Reduced proliferation was also identified in a clonogenic assay and a CFSE assay (p < 0.05) due to the MTX treatment. A reduction in the G2/M and S phases was observed accompanied by apoptosis induction with increased sub G0 phase and annexin V FITC staining. Effect of MTX was evidenced in vivo on the wound closure process after day 10 (p < 0.05) with alterations in tissue architecture and remodeling. There is a marked effect of MTX on wound healing in vivo in Skh1 mice with implications for long-term therapy and surgical interventions.

Subclinical inflammation in the preclinical phase of rheumatoid arthritis might contribute to articular joint damage.

The first degree relatives of rheumatoid arthritis (RA) patients have a higher risk of developing RA, which is related to the expression of autoantibodies against citrullinated proteins (ACPA). Remarkably, prior to the onset of RA, cartilage damage is already initiated, whereas ACPA autoantibodies are already expressed. Here we show that both TNF-α and IL-6 are also increased prior to the onset of RA. Furthermore, when the levels of DKK1 and Sclerostin were evaluated in first degree relatives of RA patients, we found that the serum levels of TNF- α correlate with the expression levels of both DKK1 and Sclerostin. Interestingly, when the disease is already established, the correlation of TNF- α with DKK1 is lost in RA patients, whereas the correlation of Sclerostin with both TNF- α and IL-6 is further increased. Our data suggest a subclinical inflammation in patients at high risk of developing RA, which might lead to an increase in the levels of both DKK1 and Sclerostin, contributing to joint damage in the preclinical phase of the disease linked to the expression of ACPA autoantibodies.

Expression and activity of AIM2-inflammasome in rheumatoid arthritis patients.

INTRODUCTION: AIM2 inflammasome activation leads to the release of IL-ß, which plays an important role in rheumatoid arthritis pathogenesis. In this work, we evaluated AIM2 expression and activity in RA patients and healthy controls. METHODS: AIM2 and RANKL expression were evaluated by flow cytometry. Inflammasome activity was determined in monocyte cultures stimulated with synthetic DNA by measuring IL-1ß levels in supernatants using an ELISA assay. The caspase-1 expression in monocytes was measured by western blot, the POP3 expression was analysed by qPCR, and serum levels of IFN-γ were evaluated using ELISA assay. RESULTS: We observed a diminution of CD14+AIM2+ cells in RA patients, associated with disease activity and evolution. Likewise, the levels of IL-1ß were increased in monocyte cultures un-stimulated and stimulated with LPS from RA patients with DAS28 ≥ 4. The Caspase-1 activity and RANKL + monocytes in RA patients were slightly increased. Finally, augmented POP3 expression and diminished IFN-γ serum levels were detected in RA patients. CONCLUSION: Our results showed that the monocytes from RA patients were prone to release IL-1ß in the absence of the AIM2 inflammasome signal. The down-regulation of AIM2 to a systemic level in RA patients might be a consequence of augmented POP3 expression and might imply the survival of pro-inflammatory cells contributing to the inflammation process.

Evaluation of SUMO1 and POU2AF1 in whole blood from rheumatoid arthritis patients and at risk relatives.

Rheumatoid arthritis (RA) is a systemic autoimmune disorder characterized by chronic and symmetrical inflammation of synovial tissue with subsequent joint destruction. SUMO1 is an important regulator of apoptosis through non-canonical mechanism in synovial fibroblasts, and POU2AF1 is a known B-cell transcriptional co-activator. The specific objective of this study was to measure the expression of SUMO1 and POU2AF1 on first-degree relatives of patients with RA and also in the preclinical and clinical stages of RA and describe their possible role in RA physiopathology. Blood samples were collected from ACPA+, ACPA-, early and established RA subjects recruited. ACPAs and CarP autoantibodies were determined by ELISA Eurodiagnostica CCplus kit according to previously described protocols. RNA was isolated from blood samples; the purity as integrity was determined. Gene expression analysis was made by RT-qPCR using specific primers for SUMO1 and POU2AF1 mRNAs; relative expression was determined according to the 2-ΔΔct method procedure. Significant differences in the expression of both, SUMO1 and POU2AF1 were identified when comparing arthritis versus healthy or ACPA+ individuals, suggesting that the down regulation of such genes starts after the onset of symptoms in RA patients. Also, a significant correlation was identified for POU2AF1 and disease progression whit a downward trend for those with established RA. The implications of such gene down regulation are discussed in the context of RA physiopathology.

Subcutaneous administration of polymerized-type I collagen for the treatment of patients with rheumatoid arthritis. An open-label pilot trial.

OBJECTIVE: To determine the efficacy, tolerance and safety of subcutaneous injections of porcine type I collagen-polyvinylpyrrolidone (PVP) in patients with rheumatoid arthritis (RA). METHODS: Eleven patients with active RA on stable therapy with methotrexate (MTX) were enrolled in a 3 month prospective and longitudinal study. Patients were treated weekly with subcutaneous injections of 0.2 ml of collagen-PVP (1.7 mg of collagen) in the 8 most painful joints. The primary endpoints included the Ritchie index (RI), swollen joint count, disease activity score (DAS), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP). The secondary endpoints included morning stiffness, pain intensity on a visual analog scale (VAS), and the Spanish-Health Assessment Questionnaire Disability Index (HAQ-DI). Improvement was determined using American College of Rheumatology (ACR) response criteria. RESULTS: Collagen-PVP was safe and well-tolerated and there were no adverse events. Patients had a statistically significant improvement (p < 0.05) in basal versus 3 month's treatment in morning stiffness (Delta -32.3, -68.6%), RI (Delta -10.2, -46.4%), swollen joint count (Delta -10.7, -71.8%), VAS (Delta -39.9, -63.8%), HAQ-DI (Delta -0.5, -48.5%), DAS (Delta -1.35, -70.5%) and ACR20, 50, and 70 (80.0%; 60.0% and 20.0% respectively). We found no differences in serologic or hematologic variables. CONCLUSION: Collagen-PVP was a safe and well-tolerated drug for the short term treatment of RA. The combination of collagen-PVP plus MTX was more efficacious than MTX alone. However, double-blind placebo-controlled phase II and III clinical trials are necessary to determine whether this drug could be useful in the longterm treatment of RA.

Valine/valine genotype at position 247 of the beta2-glycoprotein I gene in Mexican patients with primary antiphospholipid syndrome: association with anti-beta2-glycoprotein I antibodies.

OBJECTIVE: To determine the polymorphism at position 247 of the beta(2)-glycoprotein I (beta(2)GPI) gene in Mexican patients with antiphospholipid syndrome (APS) and to compare these data in patients with or without antibodies to beta(2)GPI and with the clinical manifestations of APS. METHODS: We studied 39 patients with primary APS and compared them with 106 clinically healthy subjects. Polymorphism was determined by polymerase chain reaction-restriction fragment length polymorphism. The presence of "true" anticardiolipin (aCL) antibodies, beta(2)GPI-dependent aCL antibodies (IgG and IgM), and phospholipid-free anti-beta(2)GPI antibodies (IgG isotype) were detected by enzyme-linked immunosorbent assay (ELISA) utilizing nonirradiated ELISA plates. Clinical manifestations associated with antiphospholipid antibodies were also evaluated. RESULTS: We found no significant differences in the genotype expression between the control group and the primary APS patients (13% with VV, 52% with VL, and 35% with LL versus 23% with VV, 51% with VL, and 26% with LL, respectively). In contrast, anti-beta(2)GPI-positive patients had significantly higher frequencies of the VV genotype and V allele expression than the control subjects and the anti-beta(2)GPI-negative patients. These genotype and allele frequencies were also significantly higher in patients with arterial thrombosis than in patients without it. Anti-beta(2)GPI-negative patients without arterial thrombosis did not express the VV genotype. We found no differences in the Val/Leu(247) polymorphism of the beta(2)GPI gene in primary APS patients with or without "true" aCL antibodies or in primary APS patients with or without beta(2)GPI-dependent aCL antibodies. CONCLUSION: Our results suggest that the VV genotype at position 247 of the beta(2)GPI gene may play a role in the generation of anti-beta(2)GPI antibodies and perhaps in the expression of arterial thrombosis in primary APS.