Influence of Blue Mussel (Mytilus edulis) Intake on Disease Activity in Female Patients with Rheumatoid Arthritis: The MIRA Randomized Cross-Over Dietary Intervention

Rheumatoid Arthritis (RA) is a chronic inflammatory disease. This study evaluates the effect of blue mussel intake on disease activity and quality of life in women with RA. Thirty-nine women with established RA and a disease activity score 28 (DAS28) >3.0 were recruited to a randomized 2 × 11-week cross-over dietary intervention. The participants continued with their medication and habitual diet and exchanged one cooked meal a day, five days a week, with a meal including 75 g blue mussels or 75 g meat. Diets were switched after an eight week washout period. Data regarding quality of life (SF-36), blood lipids, erythrocyte sediment rate (ESR), C-reactive protein (CRP) and tender and swollen joints were examined at the start and end of each dietary period. Thirty women completed one period, and twenty-three completed both. Intake of the blue mussel diet led to a significant reduction of DAS28-CRP (p = 0.048), but not DAS28. The number of EULAR (European League Against Rheumatism) criteria moderate and good responders were higher when consuming blue mussel diet (p = 0.036). Blood lipids did not change. To conclude, blue mussel intake reduced disease symptoms in women with RA and improved perceived health. The reported effects need to be confirmed by non-patient reported outcomes, such as inflammation markers

Antigen-Specific Gene Therapy after Immunisation Reduces the Severity of Collagen-Induced Arthritis

Reestablishment of tolerance induction in rheumatoid arthritis (RA) would be an optimal treatment with few, if any, side effects. However, to develop such a treatment further insights in the immunological mechanisms governing tolerance are needed. We have developed a model of antigen-specific tolerance in collagen type II (CII) induced arthritis (CIA) using lentivirus-based gene therapy. The immunodominant epitope of CII was inserted into a lentivirus vector to achieve expression on the MHC class II molecule and the lentiviral particles were subsequently intravenously injected at different time points during CIA. Injection of lentiviral particles in early phases of CIA, that is, at day 7 or day 26 after CII immunisation, partially prevented development of arthritis, decreased the serum levels of CII-specific IgG antibodies, and enhanced the suppressive function of CII-specific T regulatory cells. When lentiviral particles were injected during manifest arthritis, that is, at day 31 after CII immunisation, the severity of arthritis progression was ameliorated, the levels of CII-specific IgG antibodies decreased and the proportion of T regulatory cells increased. Thus, antigen-specific gene therapy is effective when administered throughout the inflammatory course of arthritis and offers a good model for investigation of the basic mechanisms during tolerance in CIA

Interleukin-17A during Local and Systemic Staphylococcus aureus-Induced Arthritis in Mice▿

Staphylococcus aureus is one of the dominant pathogens that induce septic arthritis in immunocompromised hosts, e.g., patients suffering from rheumatoid arthritis treated with immunosuppressive drugs. S. aureus-induced arthritis leads to severe joint destruction and high mortality despite antibiotic treatment. Recently, interleukin-17A (IL-17A) has been discovered to be an important mediator of aseptic arthritis both in mice and humans, but its function in S. aureus-induced arthritis is largely unknown. Here, we investigated the role of IL-17A in host defense against arthritis following systemic and local S. aureus infection in vivo. IL-17A knockout mice and wild-type mice were inoculated systemically (intravenously) or locally (intra-articularly) with S. aureus. During systemic infection, IL-17A knockout mice lost significantly more weight than the wild-type mice did, but no differences were found in the mortality rate. The absence of IL-17A had no impact on clinical arthritis development but led to increased histopathological erosivity late during systemic S. aureus infection. Bacterial clearance in kidneys was increased in IL-17A knockout mice compared to the level in wild-type mice only 1 day after bacterial inoculation. During systemic S. aureus infection, serum IL-17F protein levels and mRNA levels in the lymph nodes were elevated in the IL-17A knockout mice compared to the level in wild-type mice. In contrast to systemic infection, the IL-17A knockout mice had increased synovitis and erosions and locally decreased clearance of bacteria 3 days after local bacterial inoculation. On the basis of these findings, we suggest that IL-17A is more important in local host defense than in systemic host defense against S. aureus-induced arthritis

Reactive Oxygen Species Produced by the NADPH Oxidase 2 Complex in Monocytes Protect Mice from Bacterial Infections

Chronic granulomatous disease (CGD) is an inherited disorder characterized by recurrent life-threatening bacterial and fungal infections. CGD results from defective production of reactive oxygen species by phagocytes caused by mutations in genes encoding the NADPH oxidase 2 (NOX2) complex subunits. Mice with a spontaneous mutation in Ncf1, which encodes the NCF1 (p47(Phox)) subunit of NOX2, have defective phagocyte NOX2 activity. These mice occasionally develop local spontaneous infections by Staphylococcus xylosus or by the common CGD pathogen Staphylococcus aureus. Ncf1 mutant mice were more susceptible to systemic challenge with these bacteria than were wild-type mice. Transgenic Ncf1 mutant mice harboring the wild-type Ncf1 gene under the human CD68 promoter (MN+ mice) gained the expression of NCF1 and functional NOX2 activity specifically in monocytes/macrophages, although minimal NOX2 activity was also detected in some CD11b(+)Ly6G(+) cells defined as neutrophils. MN+ mice did not develop spontaneous infection and were more resistant to administered staphylococcal infections compared with MN- mice. Most strikingly, MN+ mice survived after being administered Burkholderia cepacia, an opportunistic pathogen in CGD patients, whereas MN- mice died. Thus, monocyte/macrophage expression of functional NCF1 protected against spontaneous and administered bacterial infections. The Journal of Immunology, 2012, 188: 5003-5011

Collagen epitope expression on B cells is sufficient to confer tolerance to collagen-induced arthritis

Background: The mechanisms underlying tolerance induction and maintenance in autoimmune arthritis remain elusive. In a mouse model of rheumatoid arthritis, collagen type II (CII)-induced arthritis, we explore the contribution of B cells to antigen-specific tolerance. Methods: To generate expression of the CII-peptide specifically on B-cell major histocompatibility complex type II, lentiviral-based gene therapy including a B-cell-specific Igk promoter was used. Results: Presentation of the CII-peptide on B cells significantly reduced the frequency and severity of arthritis as well as the serum levels of CII -specific IgG antibodies. Further, both frequency and suppressive function of regulatory T cells were increased in tolerized mice. Adoptive transfer of regulatory T cells from tolerized mice to naive mice ameliorated the development of CII-induced arthritis. Conclusion: Our data suggest that endogenous presentation of the CII-peptide on B cells is one of the key contributors to arthritis tolerance induction and maintenance

Disease-Dependent Local IL-10 Production Ameliorates Collagen Induced Arthritis in Mice

<div><p>Rheumatoid arthritis (RA) is a chronic destructive autoimmune disease characterised by periods of flare and remission. Today’s treatment is based on continuous immunosuppression irrespective of the patient’s inflammatory status. When the disease is in remission the therapy is withdrawn but withdrawal attempts often results in inflammatory flares, and re-start of the therapy is commenced when the inflammation again is prominent which leads both to suffering and increased risk of tissue destruction. An attractive alternative treatment would provide a disease-regulated therapy that offers increased anti-inflammatory effect during flares and is inactive during periods of remission. To explore this concept we expressed the immunoregulatory cytokine interleukin (IL)-10 gene under the control of an inflammation dependent promoter in a mouse model of RA - collagen type II (CII) induced arthritis (CIA). Haematopoetic stem cells (HSCs) were transduced with lentiviral particles encoding the IL-10 gene (LNT-IL-10), or a green fluorescence protein (GFP) as control gene (LNT-GFP), driven by the inflammation-dependent IL-1/IL-6 promoter. Twelve weeks after transplantation of transduced HSCs into DBA/1 mice, CIA was induced. We found that LNT-IL-10 mice developed a reduced severity of arthritis compared to controls. The LNT-IL-10 mice exhibited both increased mRNA expression levels of IL-10 as well as increased amount of IL-10 produced by B cells and non-B APCs locally in the lymph nodes compared to controls. These findings were accompanied by increased mRNA expression of the IL-10 induced suppressor of cytokine signalling 1 (SOCS1) in lymph nodes and a decrease in the serum protein levels of IL-6. We also found a decrease in both frequency and number of B cells and serum levels of anti-CII antibodies. Thus, inflammation-dependent IL-10 therapy suppresses experimental autoimmune arthritis and is a promising candidate in the development of novel treatments for RA.</p> </div

Levels of IL-10 mRNA, intracellular IL-10 production and SOCS expression

<p>(<b>A</b>)<b>.</b> Levels of IL-10 mRNA expression in lymph nodes at day 42 in LNT-GFP or LNT-IL-10 mice. (<b>B</b>) The amount of IL-10/cell measured as geometric mean flourescent intensity (MFI) in lymph node CD19⁺MHC II⁺B cells, (<b>C</b>) in lymph node CD19^-MHC II⁺non-B APCs (<b>D</b>) in splenic B cells, (<b>E</b>) in splenic non-B APCs. (<b>F</b>) Typical gating for intracellular cytokine staining showing one sample from an LNT-GFP mouse and an LNT-IL-10 mouse (<b>G</b>) Levels of mRNA SOCS1 and 3 expression in draining lymph nodes at day 42. In <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0049731#pone-0049731-g002" target="_blank">figure 2A–E and G</a> data were analysed by Mann-Whitney U-test. Closed circles represents LNT-GFP and open circles LNT-IL-10 mice.</p

Levels of IL-6 and anti-CII antibodies

<p>(<b>A</b>) Serum protein levels of IL-6 (<b>B</b>) and serum levels of anti-CII IgG were analysed at days 29 and 42 after CII immunisation. Analysed by Mann-Whitney U-test. Closed circles represents LNT-GFP and open circles LNT-IL-10 mice.</p

Lentiviral gene constructs and clinical development of arthritis.

<p>(<b>A</b>) Lentiviral constructs: LNT-GFP and LNT-IL-10. LTR; long terminal repeat, cPPT; central polypurine tract, pA; polyadenylic acid tail, WPRE; Woodchuck post-transcriptional regulatory element, IL-1E; Interleukin-1 enhancer, IL-6 promoter. (<b>B</b>) Severity of arthritis (mean arthritis score ± SEM). LNT-GFP (day 0–42 n = 18, day 44–49 n = 10) and LNT-IL-10 (day 0–42 n = 25, day 44–49 n = 14)). (<b>C</b>) Histopathological severity of synovitis and cartilage and bone erosivity measured as histological severity score (Y-axis) ranging from 0–3. Data in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0049731#pone-0049731-g001" target="_blank">figure 1B and C</a> were analysed by Mann-Whitney U-test. Closed circles represents LNT-GFP and open circles LNT-IL-10 mice. Bars in 1C represent the median.</p