| 1. |
- Zhang, Yuan, et al.
(författare)
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Recombinant Adiponectin Induces the Production of Pro-Inflammatory Chemokines and Cytokines in Circulating Mononuclear Cells and Fibroblast-Like Synoviocytes From Non-Inflamed Subjects
- 2021
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Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Adiponectin is an adipokine with a modulatory role in metabolism and exerting both anti- and pro-inflammatory effects. Levels of adiponectin are increased in serum and synovial fluid from patients with rheumatoid arthritis (RA). Adiponectin is able to stimulate the production of different pro-inflammatory factors from peripheral blood mononuclear cells (PBMCs) and fibroblast-like synoviocytes (FLS) from subjects with established RA. As increased circulating adiponectin levels are a risk factor for future development of RA in subjects with obesity, we hypothesize that adiponectin is implicated in the development of RA at an early stage by initiating the pro-inflammatory processes associated with the disease pathogenesis. Therefore, we aimed to determine if adiponectin is able to induce pro-inflammatory responses in cells involved in the pathogenesis of RA, but collected from subjects without any known inflammatory disease. PBMCs and FLS were obtained from non-inflamed subjects and stimulated with 5 mu g/ml human recombinant adiponectin. Supernatants collected after 48 h were analyzed for the production of 13 chemokines and 12 cytokines using multiplex assay and ELISA. Adiponectin significantly stimulated the production of CXCL1, CXCL5, and interleukin (IL)-6 in both PBMCs and FLS, whereas it induced CCL20, CCL4, CCL3, CCL17, tumor necrosis factor (TNF), granulocyte-macrophage colony-stimulating factor and IL-10 only in PBMCs, and CXCL8, CXCL10, CCL5, CCL11, and CCL2 only in FLS. Pre-stimulation with TNF of FLS from non-inflamed subjects did not significantly enhance the release of most pro-inflammatory factors compared to adiponectin alone. Our findings indicate that PBMCs and FLS from non-inflamed subjects react to adiponectin stimulation with the secretion of several pro-inflammatory chemokines and cytokines. These results suggest that adiponectin is able to initiate pro-inflammatory responses in cells from non-inflamed subjects and support the hypothesis that adiponectin is implicated in the early phases of RA pathogenesis.
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| 2. |
- Aldridge, Jonathan, et al.
(författare)
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Blood PD-1+TFh and CTLA-4+CD4+ T cells predict remission after CTLA-4Ig treatment in early rheumatoid arthritis.
- 2022
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Ingår i: Rheumatology (Oxford, England). - : Oxford University Press (OUP). - 1462-0324 .- 1462-0332. ; 61:3, s. 1233-1242
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Tidskriftsartikel (refereegranskat)abstract
- Treatment with CTLA-4Ig blocks T cell activation and is clinically effective in rheumatoid arthritis (RA). However, it is unknown if specific CD4+ T cell subsets in blood at baseline predict remission after CTLA-4Ig, or other biological treatments with different modes of action, and how treatment affects CD4+ T cells in patients with untreated early RA (eRA).This study included 60 patients with untreated eRA from a larger randomised trial. They were treated with methotrexate combined with CTLA-4Ig (abatacept, n=17), anti-IL6 receptor (tocilizumab, n=21) or anti-TNF (certolizumab-pegol, n=22). Disease activity was assessed by clinical disease activity index (CDAI), DAS28, swollen joint counts, tender joint counts, CRP and ESR. The primary outcome was CDAI remission (CDAI≤2.8) at week 24. Proportions of 12 CD4+ T cell subsets were measured by flow cytometry at baseline and after 4, 12 and 24weeks of treatment.In patients treated with CTLA-4Ig, the proportions of PD-1+TFh and CTLA-4+ conventional CD4+ T cells at baseline predicted CDAI remission at week 24. CD4+ T cell subset proportions could not predict remission after treatment with anti-IL6R or anti-TNF. The percentage of regulatory T cells (Tregs) expressing CTLA-4 decreased in all treatment arms by 24weeks, but only CTLA-4Ig treatment significantly reduced the proportions of Tregs and PD-1+T follicular helper (TFh) cells.These findings indicate that circulating proportions PD-1+TFh and CTLA-4+ conventional CD4+ T cells at baseline may serve as predictive biomarkers for remission in early RA after CTLA-4Ig treatment.
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| 3. |
- Aldridge, Jonathan, et al.
(författare)
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T helper cells in synovial fluid of patients with rheumatoid arthritis primarily have a Th1 and a CXCR3(+)Th2 phenotype
- 2020
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Ingår i: Arthritis Research & Therapy. - : Springer Science and Business Media LLC. - 1478-6354 .- 1478-6362. ; 22:1
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Tidskriftsartikel (refereegranskat)abstract
- Background The majority of CD4(+)T helper (Th) cells found in the synovial fluid (SF) of patients with rheumatoid arthritis (RA) express CXCR3, a receptor associated with Th1 cells. In blood, subsets of Th2 and Th17 cells also express CXCR3, but it is unknown if these cells are present in RA SF or how cytokines from these subsets affect cytokine/chemokine secretion by fibroblast-like synoviocytes (FLS) from patients with RA. Methods We examined the proportions of Th1, Th2, CXCR3(+)Th2, Th17, CXCR3(+)Th17, Th1Th17, peripheral T helper (TPh) and T follicular helper (TFh) cells in paired SF and blood, as well as the phenotype of TPh and TFh cells in RA SF (n = 8), by the use of flow cytometry. We also examined the cytokine/chemokine profile in paired SF and plasma (n = 8) and in culture supernatants of FLS from patients with chronic RA (n = 7) stimulated with Th-associated cytokines, by the use of cytometric bead arrays and ELISA. Cytokine receptor expression in FLS (n = 3) were assessed by the use of RNA sequencing and qPCR. Results The proportions of Th1 and CXCR3(+)Th2 cells were higher in SF than in blood (P < 0.05). TPh and PD-1(high)TFh in RA SF were primarily of a Th1 and a CXCR3(+)Th2 phenotype. Moreover, the levels of CXCL9, CXCL10, CCL20, CCL2, CXCL8, IL-6 and IL-10 were higher in SF than in plasma (P < 0.05). Lastly, IL-4, IL-13 and IL-17A induced RA FLS to secrete proinflammatory IL-6, CCL2, CXCL1 and CXCL8, while IFN gamma mainly induced CXCL10. Conclusion These findings indicate that not only Th1 but also CXCR3(+)Th2 cells may have a pathogenic role in RA synovial inflammation.
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| 4. |
- Hetland, M. L., et al.
(författare)
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Active conventional treatment and three different biological treatments in early rheumatoid arthritis: phase IV investigator initiated, randomised, observer blinded clinical trial
- 2020
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Ingår i: Bmj-British Medical Journal. - : BMJ. - 1756-1833. ; 371
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE To evaluate and compare benefits and harms of three biological treatments with different modes of action versus active conventional treatment in patients with early rheumatoid arthritis. DESIGN Investigator initiated, randomised, open label, blinded assessor, multiarm, phase IV study. SETTING Twenty nine rheumatology departments in Sweden, Denmark, Norway, Finland, the Netherlands, and Iceland between 2012 and 2018. PARTICIPANTS Patients aged 18 years and older with treatment naive rheumatoid arthritis, symptom duration less than 24 months, moderate to severe disease activity, and rheumatoid factor or anti-citrullinated protein antibody positivity, or increased C reactive protein. INTERVENTIONS Randomised 1:1:1:1, stratified by country, sex, and anti-citrullinated protein antibody status. All participants started methotrexate combined with (a) active conventional treatment (either prednisolone tapered to 5 mg/day, or sulfasalazine combined with hydroxychloroquine and intraarticular corticosteroids), (b) certolizumab pegol, (c) abatacept, or (d) tocilizumab. MAIN OUTCOME MEASURES The primary outcome was adjusted clinical disease activity index remission (CDAI <= 2.8) at 24 weeks with active conventional treatment as the reference. Key secondary outcomes and analyses included CDAI remission at 12 weeks and over time, other remission criteria, a non-inferiority analysis, and harms. RESULTS 812 patients underwent randomisation. The mean age was 54.3 years (standard deviation 14.7) and 68.8% were women. Baseline disease activity score of 28 joints was 5.0 (standard deviation 1.1). Adjusted 24 week CDAI remission rates were 42.7% (95% confidence interval 36.1% to 49.3%) for active conventional treatment, 46.5% (39.9% to 53.1%) for certolizumab pegol, 52.0% (45.5% to 58.6%) for abatacept, and 42.1% (35.3% to 48.8%) for tocilizumab. Corresponding absolute differences were 3.9% (95% confidence interval -5.5% to 13.2%) for certolizumab pegol, 9.4% (0.1% to 18.7%) for abatacept, and -0.6% (-10.1% to 8.9%) for tocilizumab. Key secondary outcomes showed no major differences among the four treatments. Differences in CDAI remission rates for active conventional treatment versus certolizumab pegol and tocilizumab, but not abatacept, remained within the prespecified non-inferiority margin of 15% (per protocol population). The total number of serious adverse events was 13 (percentage of patients who experienced at least one event 5.6%) for active conventional treatment, 20 (8.4%) for certolizumab pegol, 10 (4.9%) for abatacept, and 10 (4.9%) for tocilizumab. Eleven patients treated with abatacept stopped treatment early compared with 20-23 patients in the other arms. CONCLUSIONS All four treatments achieved high remission rates. Higher CDAI remission rate was observed for abatacept versus active conventional treatment, but not for certolizumab pegol or tocilizumab versus active conventional treatment. Other remission rates were similar across treatments. Non-inferiority analysis indicated that active conventional treatment was non-inferior to certolizumab pegol and tocilizumab, but not to abatacept. The results highlight the efficacy and safety of active conventional treatment based on methotrexate combined with corticosteroids, with nominally better results for abatacept, in treatment naive early rheumatoid arthritis.
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| 5. |
- Andersson, Maria L.E., et al.
(författare)
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Autoantibodies to Disease-Related Proteins in Joints as Novel Biomarkers for the Diagnosis of Rheumatoid Arthritis
- 2023
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Ingår i: Arthritis & Rheumatology. - : Wiley. - 2326-5191 .- 2326-5205. ; 75:7, s. 1110-1119
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Tidskriftsartikel (refereegranskat)abstract
- Objective. This study was undertaken to develop and characterize a multiplex immunoassay for detection of autoantibodies against peptides derived from proteins known to play a role in development of arthritis and that are also expressed in joints.Methods. We selected peptides from the human counterpart of proteins expressed in the joints, based on mouse models that showed these to be targeted by pathogenic or regulatory antibodies in vivo. Using bead-based flow immunoassays measuring IgG antibodies, we selected triple helical or cyclic peptides, containing the epitopes, to avoid collinear reactivity. We characterized the analytical performance of the immunoassay and then validated it in 3 independent rheumatoid arthritis (RA) cohorts (n = 2,110), Swedish age- and sex-matched healthy controls, and patients with osteoarthritis (OA), patients with psoriatic arthritis (PsA), and patients with systemic lupus erythematosus (SLE).Results. Screening assays showed 5 peptide antigens that discriminated RA patients from healthy controls with 99% specificity (95% confidence interval [CI] 98-100%). In our validation studies, we reproduced the discriminatory capacity of the autoantibodies in 2 other RA cohorts, showing that the autoantibodies had high discriminatory capacity for RA versus OA, PsA, and SLE. The novel biomarkers identified 22.5% (95% CI 19-26%) of early RA patients seronegative for anti-cyclic citrullinated peptide and rheumatoid factor. The usefulness of the biomarkers in identifying seronegative RA patients was confirmed in validation studies using 2 independent cohorts of RA patients and cohorts of patients with OA, PsA, and SLE.Conclusion. A multiplex immunoassay with peptides from disease-related proteins in joints was found to be useful for detection of specific autoantibodies in RA serum. Of note, this immunoassay had high discriminatory capacity for early seronegative RA.
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| 6. |
- Bergström, Beatrice, et al.
(författare)
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The Rheumatoid Arthritis Risk Gene AIRE Is Induced by Cytokines in Fibroblast-Like Synoviocytes and Augments the Pro-inflammatory Response
- 2019
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Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- The autoimmune regulator AIRE controls the negative selection of self-reactive T-cells as well as the induction of regulatory T-cells in the thymus by mastering the transcription and presentation of tissue restricted antigens (TRAs) in thymic cells. However, extrathymic AIRE expression of hitherto unknown clinical significance has also been reported. Genetic polymorphisms of AIRE have been associated with rheumatoid arthritis (RA), but no specific disease-mediating mechanism has been identified. Rheumatoid arthritis is characterized by a systemic immune activation and arthritis. Activated fibroblast-like synoviocytes (FLS) are key effector cells, mediating persistent inflammation, and destruction of joints. In this study, we identified AIRE as a cytokine-induced RA risk gene in RA FLS and explored its role in these pathogenic stroma cells. Using RNA interference and RNA sequencing we show that AIRE does not induce TRAs in FLS, but augments the pro-inflammatory response induced by tumor necrosis factor and interleukin-1 beta by promoting the transcription of a set of genes associated with systemic autoimmune disease and annotated as interferon-gamma regulated genes. In particular, AIRE promoted the production and secretion of a set of chemokines, amongst them CXCL10, which have been associated with disease activity in RA. Finally, we demonstrate that AIRE is expressed in podoplanin positive FLS in the lining layer of synovial tissue from RA patients. These findings support a novel pro-inflammatory role of AIRE at peripheral inflammatory sites and provide a potential pathological mechanism for its association with RA.
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| 7. |
- Svensson, Mattias, 1982, et al.
(författare)
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Fms-like tyrosine kinase 3 ligand controls formation of regulatory T cells in autoimmune arthritis.
- 2013
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Fms-like tyrosine kinase 3 ligand (Flt3L) is known as the primary differentiation and survival factor for dendritic cells (DCs). Furthermore, Flt3L is involved in the homeostatic feedback loop between DCs and regulatory T cell (Treg). We have previously shown that Flt3L accumulates in the synovial fluid in rheumatoid arthritis (RA) and that local exposure to Flt3L aggravates arthritis in mice, suggesting a possible involvement in RA pathogenesis. In the present study we investigated the role of Flt3L on DC populations, Tregs as well as inflammatory responses in experimental antigen-induced arthritis. Arthritis was induced in mBSA-immunized mice by local knee injection of mBSA and Flt3L was provided by daily intraperitoneal injections. Flow cytometry analysis of spleen and lymph nodes revealed an increased formation of DCs and subsequently Tregs in mice treated with Flt3L. Flt3L-treatment was also associated with a reduced production of mBSA specific antibodies and reduced levels of the pro-inflammatory cytokines IL-6 and TNF-α. Morphological evaluation of mBSA injected joints revealed reduced joint destruction in Flt3L treated mice. The role of DCs in mBSA arthritis was further challenged in an adoptive transfer experiment. Transfer of DCs in combination with T-cells from mBSA immunized mice, predisposed naïve recipients for arthritis and production of mBSA specific antibodies. We provide experimental evidence that Flt3L has potent immunoregulatory properties. Flt3L facilitates formation of Treg cells and by this mechanism reduces severity of antigen-induced arthritis in mice. We suggest that high systemic levels of Flt3L have potential to modulate autoreactivity and autoimmunity.
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| 8. |
- Thorarinsdottir, Katrin, et al.
(författare)
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Cartilage destruction in early rheumatoid arthritis patients correlates with CD21−/low double-negative B cells
- 2024
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Ingår i: Arthritis Research and Therapy. - 1478-6354 .- 1478-6362. ; 26:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Involvement of B cells in the pathogenesis of rheumatoid arthritis (RA) is supported by the presence of disease-specific autoantibodies and the efficacy of treatment directed against B cells. B cells that express low levels of or lack the B cell receptor (BCR) co-receptor CD21, CD21−/low B cells, have been linked to autoimmune diseases, including RA. In this study, we characterized the CD21+ and CD21−/low B cell subsets in newly diagnosed, early RA (eRA) patients and investigated whether any of the B cell subsets were associated with autoantibody status, disease activity and/or joint destruction. Methods: Seventy-six eRA patients and 28 age- and sex-matched healthy donors were recruited. Multiple clinical parameters were assessed, including disease activity and radiographic joint destruction. B cell subsets were analysed in peripheral blood (PB) and synovial fluid (SF) using flow cytometry. Results: Compared to healthy donors, the eRA patients displayed an elevated frequency of naïve CD21+ B cells in PB. Amongst memory B cells, eRA patients had lower frequencies of the CD21+CD27+ subsets and CD21−/low CD27+IgD+ subset. The only B cell subset found to associate with clinical factors was the CD21−/low double-negative (DN, CD27−IgD−) cell population, linked with the joint space narrowing score, i.e. cartilage destruction. Moreover, in SF from patients with established RA, the CD21−/low DN B cells were expanded and these cells expressed receptor activator of the nuclear factor κB ligand (RANKL). Conclusions: Cartilage destruction in eRA patients was associated with an expanded proportion of CD21−/low DN B cells in PB. The subset was also expanded in SF from established RA patients and expressed RANKL. Taken together, our results suggest a role for CD21−/low DN in RA pathogenesis.
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| 9. |
- Ali, Liaqat, et al.
(författare)
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The O-glycomap of Lubricin, a Novel Mucin Responsible for Joint Lubrication, Identified by Site-specific Glycopeptide Analysis
- 2014
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Ingår i: Molecular & Cellular Proteomics. - 1535-9476. ; 13:12, s. 3396-3409
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Tidskriftsartikel (refereegranskat)abstract
- The lubricative, heavily glycosylated mucin-like synovial glycoprotein lubricin has previously been observed to contain glycosylation changes related to rheumatoid and osteoarthritis. Thus, a site-specific investigation of the glycosylation of lubricin was undertaken, in order to further understand the pathological mechanisms involved in these diseases. Lubricin contains an serine/threonine/proline (STP)-rich domain composed of imperfect tandem repeats (EPAPTTPK), the target for O-glycosylation. In this study, using a liquid chromatography-tandem mass spectrometry approach, employing both collision-induced and electron-transfer dissociation fragmentation methods, we identified 185 O-glycopeptides within the STP-rich domain of human synovial lubricin. This showed that adjacent threonine residues within the central STP-rich region could be simultaneously and/or individually glycosylated. In addition to core 1 structures responsible for biolubrication, core 2 O-glycopeptides were also identified, indicating that lubricin glycosylation may have other roles. Investigation of the expression of polypeptide N-acetylgalactosaminyltransferase genes was carried out using cultured primary fibroblast-like synoviocytes, a cell type that expresses lubricin in vivo. This analysis showed high mRNA expression levels of the less understood polypeptide N-acetylgalactosaminyltransferase 15 and 5 in addition to the ubiquitously expressed polypeptide N-acetylgalactosaminyltransferase 1 and 2 genes. This suggests that there is a unique combination of transferase genes important for the O-glycosylation of lubricin. The site-specific glycopeptide analysis covered 82% of the protein sequence and showed that lubricin glycosylation displays both micro-and macroheterogeneity. The density of glycosylation was shown to be high: 168 sites of O-glycosylation, predominately sialylated, were identified. These glycosylation sites were focused in the central STP-rich region, giving the domain a negative charge. The more positively charged lysine and arginine residues in the N and C termini suggest that synovial lubricin exists as an amphoteric molecule. The identification of these unique properties of lubricin may provide insight into the important low-friction lubricating functions of lubricin during natural joint movement.
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| 10. |
- Baran, M, et al.
(författare)
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SURVIVIN IS AN ESSENTIAL MEDIATOR OF ARTHRITIS INTERACTING WITH UROKINASE SIGNALLING.
- 2009
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Ingår i: Journal of cellular and molecular medicine. - : Wiley. - 1582-4934 .- 1582-1838. ; 13:9B, s. 3797-3808
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT Proto-oncogene survivin has recently been identified as a prognostic marker distinguishing patients with destructive rheumatoid arthritis (RA). In the present material of 132 RA patients and 82 controls the levels of survivin correlated to urokinase (uPA) (r=0.46), a plasminogen activator over expressed in inflamed joints and known to exhibit potent arthritogenic properties. Here we evaluate the functional relationship between these proteins using primary synovial fibroblasts and leukocytes of RA patients, human monocytic (THP-1) and fibroblast (MRC-5) cell lines. Using inhibitors of intracellular signalling we show that uPA and survivin share common transduction pathways being in synovial fibroblasts dependent on the activity of tyrosine kinases, PI3-kinase and MEK. Moreover, uPA production is significantly reduced in fibroblasts if survivin synthesis has been silenced by siRNA. Importantly, silencing of survivin in fibroblasts prevented their invasive growth in knee joints of SCID mice. Interaction of uPA with receptor up regulates survivin expression in leukocytes. In turn, survivin is required for the upregulation of uPA receptor on cell surface. These findings indicate that survivin is an essential mediator of arthritogenic properties of uPA regulating its synthesis in synovial fibroblasts and uPAR expression in leukocytes. Close correlation between survivin and uPA levels in patients with RA supports the importance of this connection for the pathogenesis of arthritis.
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| 11. |
- Bergström, Beatrice, et al.
(författare)
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Methotrexate inhibits effects of platelet-derived growth factor and interleukin-1β on rheumatoid arthritis fibroblast-like synoviocytes
- 2018
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Ingår i: Arthritis Research and Therapy. - : Springer Science and Business Media LLC. - 1478-6354 .- 1478-6362. ; 20:49
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Tidskriftsartikel (refereegranskat)abstract
- Background: A key feature of joints in rheumatoid arthritis (RA) is the formation of hyperplastic destructive pannus tissue, which is orchestrated by activated fibroblast-like synoviocytes (FLS). We have demonstrated that the RA risk gene and tumor suppressor Limb bud and heart development (LBH) regulates cell cycle progression in FLS. Methotrexate (MTX) is the first-line treatment for RA, but its mechanisms of action remain incompletely understood. Here, we studied the effects of MTX on mitogen-induced FLS proliferation and expression of cell cycle regulators in vitro. Methods: Primary FLS from patients with RA or osteoarthritis were stimulated with the mitogen platelet-derived growth factor (PDGF) and the cytokine interleukin-1β (IL-1β) in the presence or absence of MTX. Cells were then subjected to qPCR for gene expression and cell cycle analysis by flow cytometry. Results: Stimulation with PDGF and IL-1β increased the percentage of FLS in the G2/M phase and shifted the cell morphology to a dendritic shape. These effects were inhibited by MTX. Furthermore, PDGF + IL-1β reduced LBH mRNA expression. However, MTX treatment yielded significantly higher transcript levels of LBH, and of CDKN1A (p21) and TP53 (p53), compared to untreated samples upon mitogen stimulation. The expression of DNA methyltransferase-1 (DNMT1) was also higher in the presence of MTX and there was strong correlation between DNMT1 and LBH expression. Conclusions: Therapeutic concentrations of MTX abolish the effects of PDGF and IL-1β on tumor suppressor expression and inhibit mitogen-promoted FLS proliferation. These data demonstrate novel and important effects of MTX on pathogenic effector cells in the joint, which might involve epigenetic mechanisms. © 2018 The Author(s).
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| 12. |
- Boström, Elisabeth Almer, 1983, et al.
(författare)
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Resistin and insulin/insulin-like growth factor signaling in rheumatoid arthritis.
- 2011
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Ingår i: Arthritis and rheumatism. - : Wiley. - 1529-0131 .- 0004-3591. ; 63:10, s. 2894-904
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Tidskriftsartikel (refereegranskat)abstract
- Human resistin has proinflammatory properties that activate NF-κB-dependent pathways, whereas its murine counterpart is associated with insulin resistance. The aim of this study was to examine potential cross-talk between resistin and insulin/insulin-like growth factor (IGF) signaling in rheumatoid arthritis (RA).
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| 13. |
- Ekwall, Anna-Karin H, et al.
(författare)
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The tumour-associated glycoprotein podoplanin is expressed in fibroblast-like synoviocytes of the hyperplastic synovial lining layer in rheumatoid arthritis.
- 2011
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Ingår i: Arthritis research & therapy. - : Springer Science and Business Media LLC. - 1478-6362. ; 13:2
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: INTRODUCTION: Activated fibroblast-like synoviocytes (FLSs) in rheumatoid arthritis (RA) share many characteristics with tumour cells and are key mediators of synovial tissue transformation and joint destruction. The glycoprotein podoplanin is upregulated in the invasive front of several human cancers and has been associated with epithelial-mesenchymal transition, increased cell migration and tissue invasion. The aim of this study was to investigate whether podoplanin is expressed in areas of synovial transformation in RA and especially in promigratory RA-FLS. METHODS: Podoplanin expression in human synovial tissue from 18 RA patients and nine osteoarthritis (OA) patients was assessed by immunohistochemistry and confirmed by Western blot analysis. The expression was related to markers of synoviocytes and myofibroblasts detected by using confocal immunofluoresence microscopy. Expression of podoplanin, with or without the addition of proinflammatory cytokines and growth factors, in primary human FLS was evaluated by using flow cytometry. RESULTS: Podoplanin was highly expressed in cadherin-11-positive cells throughout the synovial lining layer in RA. The expression was most pronounced in areas with lining layer hyperplasia and high matrix metalloproteinase 9 expression, where it coincided with upregulation of α-smooth muscle actin (α-sma). The synovium in OA was predominantly podoplanin-negative. Podoplanin was expressed in 50% of cultured primary FLSs, and the expression was increased by interleukin 1β, tumour necrosis factor α and transforming growth factor β receptor 1. CONCLUSIONS: Here we show that podoplanin is highly expressed in FLSs of the invading synovial tissue in RA. The concomitant upregulation of α-sma and podoplanin in a subpopulation of FLSs indicates a myofibroblast phenotype. Proinflammatory mediators increased the podoplanin expression in cultured RA-FLS. We conclude that podoplanin might be involved in the synovial tissue transformation and increased migratory potential of activated FLSs in RA.
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| 14. |
- Hammaker, D., et al.
(författare)
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LBH Gene Transcription Regulation by the Interplay of an Enhancer Risk Allele and DNA Methylation in Rheumatoid Arthritis
- 2016
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Ingår i: Arthritis & Rheumatology. - : Wiley. - 2326-5191. ; 68:11, s. 2637-2645
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveTo identify nonobvious therapeutic targets for rheumatoid arthritis (RA), we performed an integrative analysis incorporating multiple omics data and the Encyclopedia of DNA Elements (ENCODE) database for potential regulatory regions. This analysis identified the limb bud and heart development (LBH) gene, which has risk alleles associated with RA/celiac disease and lupus, and can regulate cell proliferation in RA. We identified a novel LBH transcription enhancer with an RA risk allele (rs906868 G [Ref]/T) 6 kb upstream of the LBH gene with a differentially methylated locus. The confluence of 3 regulatory elements, rs906868, an RA differentially methylated locus, and a putative enhancer, led us to investigate their effects on LBH regulation in fibroblast-like synoviocytes (FLS). MethodsWe cloned the 1.4-kb putative enhancer with either the rs906868 Ref allele or single-nucleotide polymorphism (SNP) variant into reporter constructs. The constructs were methylated in vitro and transfected into cultured FLS by nucleofection. ResultsWe found that both variants increased transcription, thereby confirming the region's enhancer function. Unexpectedly, the transcriptional activity of the Ref risk allele was significantly lower than that of the SNP variant and is consistent with low LBH levels as a risk factor for aggressive FLS behavior. Using RA FLS lines with a homozygous Ref or SNP allele, we confirmed that homozygous Ref lines expressed lower LBH messenger RNA levels than did the SNP lines. Methylation significantly reduced enhancer activity for both alleles, indicating that enhancer function is dependent on its methylation status. ConclusionThis study shows how the interplay between genetics and epigenetics can affect expression of LBH in RA.
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| 15. |
- Hultgård-Ekwall, Anna-Karin H, et al.
(författare)
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Network organization of interstitial connective tissue cells in the human endolymphatic duct
- 2003
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Ingår i: Journal of Histochemistry and Cytochemistry. - : SAGE Publications. - 0022-1554 .- 1551-5044. ; 51:11, s. 1491-500
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Tidskriftsartikel (refereegranskat)abstract
- The human endolymphatic duct (ED) and sac of the inner ear have been suggested to control endolymph volume and pressure. However, the physiological mechanisms for these processes remain obscure. We investigated the organization of the periductal interstitial connective tissue cells and extracellular matrix (ECM) in four freshly fixed human EDs by transmission electron microscopy and by immunohistochemistry. The unique surgical material allowed a greatly improved structural and epitopic preservation of tissue. Periductal connective tissue cells formed frequent intercellular contacts and focally occurring electron-dense contacts to ECM structures, creating a complex tissue network. The connective tissue cells also formed contacts with the basal lamina of the ED epithelium and the bone matrix, connecting the ED with the surrounding bone of the vestibular aqueduct. The interstitial connective tissue cells were non-endothelial and non-smooth muscle fibroblastoid cells. We suggest that the ED tissue network forms a functional mechanical entity that takes part in the control of inner ear fluid pressure and endolymph resorption.
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| 16. |
- Jin, Chunsheng, et al.
(författare)
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Human Synovial Lubricin Expresses Sialyl Lewis x Determinant and Has L-selectin Ligand Activity
- 2012
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 287:43, s. 35922-35933
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Tidskriftsartikel (refereegranskat)abstract
- Lubricin (or proteoglycan 4 (PRG4)) is an abundant mucin-like glycoprotein in synovial fluid (SF) and a major component responsible for joint lubrication. In this study, it was shown that O-linked core 2 oligosaccharides (Gal beta 1-3(GlcNAc beta 1-6)GalNAc alpha 1-Thr/Ser) on lubricin isolated from rheumatoid arthritis SF contained both sulfate and fucose residues, and SF lubricin was capable of binding to recombinant L-selectin in a glycosylation-dependent manner. Using resting human polymorphonuclear granulocytes (PMN) from peripheral blood, confocal microscopy showed that lubricin coated circulating PMN and that it partly co-localized with L-selectin expressed by these cells. In agreement with this, activation-induced shedding of L-selectin also mediated decreased lubricin binding to PMN. It was also found that PMN recruited to inflamed synovial area and fluid in rheumatoid arthritis patients kept a coat of lubricin. These observations suggest that lubricin is able to bind to PMN via an L-selectin-dependent and -independent manner and may play a role in PMN-mediated inflammation.
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| 17. |
- Svensson, Mattias N D, et al.
(författare)
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Synoviocyte-targeted therapy synergizes with TNF inhibition in arthritis reversal.
- 2020
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Ingår i: Science advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 6:26
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Tidskriftsartikel (refereegranskat)abstract
- Fibroblast-like synoviocytes (FLS) are joint-lining cells that promote rheumatoid arthritis (RA) pathology. Current disease-modifying antirheumatic agents (DMARDs) operate through systemic immunosuppression. FLS-targeted approaches could potentially be combined with DMARDs to improve control of RA without increasing immunosuppression. Here, we assessed the potential of immunoglobulin-like domains 1 and 2 (Ig1&2), a decoy protein that activates the receptor tyrosine phosphatase sigma (PTPRS) on FLS, for RA therapy. We report that PTPRS expression is enriched in synovial lining RA FLS and that Ig1&2 reduces migration of RA but not osteoarthritis FLS. Administration of an Fc-fusion Ig1&2 attenuated arthritis in mice without affecting innate or adaptive immunity. Furthermore, PTPRS was down-regulated in FLS by tumor necrosis factor (TNF) via a phosphatidylinositol 3-kinase-mediated pathway, and TNF inhibition enhanced PTPRS expression in arthritic joints. Combination of ineffective doses of TNF inhibitor and Fc-Ig1&2 reversed arthritis in mice, providing an example of synergy between FLS-targeted and immunosuppressive DMARD therapies.
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