| 11. |
- Haag, Sabrina, et al.
(författare)
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Positional Identification of RT1-B (HLA-DQ) as Susceptibility Locus for Autoimmune Arthritis
- 2015
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Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 194:6, s. 2539-2550
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Tidskriftsartikel (refereegranskat)abstract
- Rheumatoid arthritis (RA) is associated with amino acid variants in multiple MHC molecules. The association to MHC class II (MHC-II) has been studied in several animal models of RA. In most cases these models depend on T cells restricted to a single immunodominant peptide of the immunizing Ag, which does not resemble the autoreactive T cells in RA. An exception is pristane-induced arthritis (PIA) in the rat where polyclonal T cells induce chronic arthritis after being primed against endogenous Ags. In this study, we used a mixed genetic and functional approach to show that RT1-Ba and RT1-Bb (RT1-B locus), the rat orthologs of HLA-DQA and HLA-DQB, determine the onset and severity of PIA. We isolated a 0.2-Mb interval within the MHC-II locus of three MHC-congenic strains, of which two were protected from severe PIA. Comparison of sequence and expression variation, as well as in vivo blocking of RT1-B and RT1-D (HLA-DR), showed that arthritis in these strains is regulated by coding polymorphisms in the RT1-B genes. Motif prediction based on MHC-II eluted peptides and structural homology modeling suggested that variants in the RT1-B P1 pocket, which likely affect the editing capacity by RT1-DM, are important for the development of PIA.
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| 12. |
- Hagert, C., et al.
(författare)
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Chronic Active Arthritis Driven by Macrophages Without Involvement of T Cells : A Novel Experimental Model of Rheumatoid Arthritis
- 2018
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Ingår i: Arthritis & Rheumatology. - Hoboken : Wiley. - 2326-5191 .- 2326-5205 .- 1529-0131. ; 70:8, s. 1343-1353
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To develop a new chronic rheumatoid arthritis model that is driven by the innate immune system. METHODS: Injection of a cocktail of 4 monoclonal antibodies against type II collagen, followed on days 5 and 60 by intraperitoneal injections of mannan (from Saccharomyces cerevisiae), was used to induce development of chronic arthritis in B10.Q mice. The role of the innate immune system as compared to the adaptive immune system in this arthritis model was investigated using genetically modified mouse strains. RESULTS: A new model of chronic relapsing arthritis was characterized in B10.Q mice, in which a persistently active, chronic disease was found. This relapsing disease was driven by macrophages lacking the ability to mount a reactive oxygen species response against pathogens, and was associated with the classical/alternative pathway, but not the lectin pathway, of complement activation. The disease was independent of Fcgamma receptor type III, and also independent of the activity of adaptive immune cells (B and T cells), indicating that the innate immune system, involving complement activation, could be the sole driver of chronicity. CONCLUSION: Chronic active arthritis can be driven innately by macrophages without the involvement of T and B cells in the adaptive immune system.
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| 13. |
- Khmaladze, Ia, et al.
(författare)
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B-cell epitope spreading and inflammation in a mouse model of arthritis is associated with a deficiency in reactive oxygen species production
- 2015
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Ingår i: European Journal of Immunology. - Weinheim : Wiley-VCH Verlagsgesellschaft. - 0014-2980 .- 1521-4141. ; 45:8, s. 2243-2251
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Tidskriftsartikel (refereegranskat)abstract
- Autoantibody-mediated inflammation contributes to the development of rheumatoid arthritis (RA), and anti-type II collagen (CII) antibodies are present in the serum, synovial fluid, and cartilage of RA patients. We had previously generated and characterized knock-in mice expressing a germline-encoded, CII-specific IgH (B10Q.ACB), which demonstrated positive selection of self-reactive B cells. Here, we show that despite the spontaneous production of CII-specific autoantibodies, B10Q.ACB mice are protected from collagen-induced arthritis. Introducing a mutation in the Ncf1 gene, leading to ROS deficiency, breaks this strong arthritis resistance. Disease development in Ncf1-mutated B10Q.ACB mice is associated with an enhanced germinal center formation but without somatic mutations of the auto-reactive B cells, increased T-cell responses and intramolecular epitope-spreading. Thus, ROS-mediated B-cell tolerance to a self-antigen could operate by limiting the expansion of the auto-reactive B-cell repertoire, which has important implications for the understanding of epitope spreading phenomena in rheumatoid arthritis and other autoimmune diseases.
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| 14. |
- Kokkonen, Heidi, et al.
(författare)
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Associations of antibodies against citrullinated peptides with human leukocyte antigen-shared epitope and smoking prior to the development of rheumatoid arthritis
- 2015
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Ingår i: Arthritis Research & Therapy. - : BioMed Central. - 1478-6354 .- 1478-6362. ; 17
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: It has previously been shown that an increased number of antibodies against citrullinated peptides/proteins (ACPA) predate the onset of rheumatoid arthritis (RA). Over time antibody positivity expands, involving more specific responses when approaching the onset of symptoms. We investigated the impact of human leukocyte antigen-shared epitope (HLA-SE) alleles and smoking on the development of ACPA, as well as in combination with ACPA during the state of quiescent autoimmunity (before the onset of symptoms), on the development of RA. Methods: Blood samples donated to the Medical Biobank of Northern Sweden from individuals prior to the onset of symptoms of RA (n = 370) and after onset (n = 203) and from population-based controls (n = 585) were used. Antibodies against 10 citrullinated peptides, fibrinogen (Fib alpha 561-583, alpha 580-600, beta 62-81a, beta 62-81b, beta 36-52), vimentin (Vim2-17, 60-75), filaggrin (CCP-1/Fil307-324),alpha-enolase (CEP-1/Eno5-21), collagen type II (citC1359-369), and anti-cyclic citrullinated peptide (CCP) 2 antibodies were analysed. Results: HLA-SE-positive individuals were more frequently positive for ACPA compared with HLA-SE-negative individuals prior to the onset of symptoms of RA, particularly for antibodies against CEP-1 and Fib beta 62-81a (72). Smoking was associated with antibodies against Vim2-17 and citC1359-369. HLA-SE and smoking showed increasing association to the presence of the antibodies closer to disease onset. The highest odds ratio (OR) for development of RA was for the combination of HLA-SE alleles and ACPA positivity, especially for antibodies against Fib beta 62-81b, CCP-1/Fil307-324, and Fib beta 36-52. A gene-environment additive interaction between smoking and HLA-SE alleles for the risk of disease development was found, with the highest OR for individuals positive for antibodies against Fib beta 36-52, CEP-1, and Fib alpha 580-600. Conclusions: The relationships between antibodies against the different ACPA specificities, HLA-SE, and smoking showed a variable pattern in individuals prior to the onset of RA. The combination of smoking and HLA-SE alleles was significantly associated with the development of some of the antibody specificities closer to onset of symptoms, and these associations remained significant at diagnosis. An additive gene-environment interaction was found for several of the antibodies for the development of RA.
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| 15. |
- Lindgren, Cecilia, et al.
(författare)
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Dynamics Determine Signaling in a Multicomponent System Associated with Rheumatoid Arthritis
- 2018
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Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 61:11, s. 4774-4790
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Tidskriftsartikel (refereegranskat)abstract
- Strategies that target multiple components are usually required for treatment of diseases originating from complex biological systems. The multicomponent system consisting of the DR4 major histocompatibility complex type II molecule, the glycopeptide CI1259-273 from type II collagen, and a T-cell receptor is associated with development of rheumatoid arthritis (RA). We introduced non-native amino acids and amide bond isosteres into CI1259-273 and investigated the effect on binding to DR4 and the subsequent T-cell response. Molecular dynamics simulations revealed that complexes between DR4 and derivatives of CI1259-273 were highly dynamic. Signaling in the overall multicomponent system was found to depend on formation of an appropriate number of dynamic intramolecular hydrogen bonds between DR4 and CI1259-273, together with the positioning of the galactose moiety of CI1259-273 in the DR4 binding groove. Interestingly, the system tolerated modifications at several positions in CI1259-273, indicating opportunities to use analogues to increase our understanding of how rheumatoid arthritis develops and for evaluation as vaccines to treat RA.
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| 16. |
- Lindgren, Cecilia, et al.
(författare)
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Hydroxyethylene isosteres introduced in type II collagen fragments substantially alter the structure and dynamics of class II MHC A(q)/glycopeptide complexes
- 2015
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Ingår i: Organic and biomolecular chemistry. - : Royal Society of Chemistry (RSC). - 1477-0520 .- 1477-0539. ; 13:22, s. 6203-6216
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Tidskriftsartikel (refereegranskat)abstract
- Class II major histocompatibility complex (MHC) proteins are involved in initiation of immune responses to foreign antigens via presentation of peptides to receptors of CD4(+) T-cells. An analogous presentation of self-peptides may lead to autoimmune diseases, such as rheumatoid arthritis (RA). The glycopeptide fragment CII259-273, derived from type II collagen, is presented by A(q) MHCII molecules in the mouse and has a key role in development of collagen induced arthritis (CIA), a validated model for RA. We have introduced hydroxyethylene amide bond isosteres at the Ala(261)-Gly(262) position of CII259-273. Biological evaluation showed that A(q) binding and T cell recognition were dramatically reduced for the modified glycopeptides, although static models predicted similar binding modes as the native type II collagen fragment. Molecular dynamics (MD) simulations demonstrated that introduction of the hydroxyethylene isosteres disturbed the entire hydrogen bond network between the glycopeptides and A(q). As a consequence the hydroxyethylene isosteric glycopeptides were prone to dissociation from A(q) and unfolding of the beta(1)-helix. Thus, the isostere induced adjustment of the hydrogen bond network altered the structure and dynamics of A(q)/glycopeptide complexes leading to the loss of A(q) affinity and subsequent T cell response.
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| 17. |
- Nandakumar, Kutty Selva, 1965-, et al.
(författare)
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Streptococcal Endo-β-N-Acetylglucosaminidase Suppresses Antibody-Mediated Inflammation In Vivo
- 2018
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Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Endo-β-N-acetylglucosaminidase (EndoS) is a family 18 glycosyl hydrolase secreted by Streptococcus pyogenes. Recombinant EndoS hydrolyzes the β-1,4-di-N-acetylchitobiose core of the N-linked complex type glycan on the asparagine 297 of the γ-chains of IgG. Here, we report that EndoS and IgG hydrolyzed by EndoS induced suppression of local immune complex (IC)-mediated arthritis. A small amount (1 µg given i.v. to a mouse) of EndoS was sufficient to inhibit IgG-mediated arthritis in mice. The presence of EndoS disturbed larger IC lattice formation both in vitro and in vivo, as visualized with anti-C3b staining. Neither complement binding in vitro nor antigen-antibody binding per se were affected. Thus, EndoS could potentially be used for treating patients with IC-mediated pathology.
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| 18. |
- Olsson, Lina M., et al.
(författare)
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A single nucleotide polymorphism in the NCF1 gene leading to reduced oxidative burst is associated with systemic lupus erythematosus
- 2017
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ Publishing Group Ltd. - 0003-4967 .- 1468-2060. ; 76:9, s. 1607-1613
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Ncf1 polymorphisms leading to low production of reactive oxygen species (ROS) are strongly associated with autoimmune diseases in animal models. The human NCF1 gene is very complex with both functional and non-functional gene copies and genotyping requires assays specific for functional NCF1 genes. We aimed at investigating association and function of the missense single nucleotide polymorphism (SNP), rs201802880 (here denoted NCF1-339) in NCF1 with systemic lupus erythematosus (SLE).METHODS: We genotyped the NCF1-339 SNP in 973 Swedish patients with SLE and 1301 controls, using nested PCR and pyrosequencing. ROS production and gene expression of type 1 interferon-regulated genes were measured in isolated cells from subjects with different NCF1-339 genotypes.RESULTS: We found an increased frequency of the NCF1-339 T allele in patients with SLE, 11% compared with 4% in controls, OR 3.0, 95% CI 2.4 to 3.9, p=7.0×10(-20). The NCF1-339 T allele reduced extracellular ROS production in neutrophils (p=0.004) and led to an increase expression of type 1 interferon-regulated genes. In addition, the NCF1-339 T allele was associated with a younger age at diagnosis of SLE; mean age 30.3 compared with 35.9, p=2.0×1(-6).CONCLUSIONS: These results clearly demonstrate that a genetically controlled reduced production of ROS increases the risk of developing SLE and confirm the hypothesis that ROS regulate chronic autoimmune inflammatory diseases.
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| 19. |
- Peleli, Maria, et al.
(författare)
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Enhanced XOR activity in eNOS-deficient mice Effects on the nitrate-nitrite-NO pathway and ROS homeostasis
- 2016
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Ingår i: Free Radical Biology & Medicine. - : Elsevier BV. - 0891-5849 .- 1873-4596. ; 99, s. 472-484
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Tidskriftsartikel (refereegranskat)abstract
- Xanthine oxidoreductase (XOR) is generally known as the final enzyme in purine metabolism and as a source of reactive oxygen species (ROS). In addition, this enzyme has been suggested to mediate nitric oxide (NO) formation via reduction of inorganic nitrate and nitrite. This NO synthase (NOS)-independent pathway for NO generation is of particular importance during certain conditions when NO bioavailability is diminished due to reduced activity of endothelial NOS (eNOS) or increased oxidative stress, including aging and cardiovascular disease. The exact interplay between NOS- and XOR-derived NO generation is not fully elucidated yet. The aim of the present study was to investigate if eNOS deficiency is associated with changes in XOR expression and activity and the possible impact on nitrite, NO and ROS homeostasis. Plasma levels of nitrate and nitrite were similar between eNOS deficient (eNOS(-/-)) and wildtype (wt) mice. XOR activity was upregulated in eNOS(-/-) compared with wt, but not in nNOS(-/-), iNOS(-/-) or wt mice treated with the non-selective NOS inhibitor L-NAME. Following an acute dose of nitrate, plasma nitrite increased more in eNOS(-/-) compared with wt, and this augmented response was abolished by the selective XOR inhibitor febuxostat. Livers from eNOS(-/-) displayed higher nitrite reducing capacity compared with wt, and this effect was attenuated by febuxostat. Dietary supplementation with nitrate increased XOR expression and activity, but concomitantly reduced superoxide generation. The latter effect was also seen in vitro after nitrite administration. Treatment with febuxostat elevated blood pressure in eNOS(-/-), but not in wt mice. A high dose of dietary nitrate reduced blood pressure in na ve eNOS(-/-) mice, and again this effect was abolished by febuxostat. In conclusion, eNOS deficiency is associated with an upregulation of XOR facilitating the nitrate-nitrite-NO pathway and decreasing the generation of ROS. This interplay between XOR and eNOS is proposed to play a significant role in NO homeostasis and blood pressure regulation.
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| 20. |
- Raposo, Bruno, et al.
(författare)
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System A amino acid transporters regulate glutamine uptake and attenuate antibody-mediated arthritis
- 2015
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Ingår i: Immunology. - Chichester : Wiley-Blackwell Publishing Inc.. - 0019-2805 .- 1365-2567. ; 146:4, s. 607-617
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Tidskriftsartikel (refereegranskat)abstract
- Proliferation of rapidly dividing bone marrow-derived cells is strongly dependent on the availability of free glutamine, whose uptake is mediated through different amino acid transporters. The sodium-coupled neutral amino acid transporter (SNAT) family was previously reported to be associated with the development of collagen-induced arthritis in mice. Here, we tested the hypothesis whether impairment of SNAT proteins influences immune cell function and in turn alters arthritis development. The 2-(methylamino)isobutyric acid (MeAIB), a SNAT-specific substrate, was used to modulate the function of SNAT proteins. We demonstrate that glutamine uptake by murine naive lymphocytes, and consequent cell proliferation, is strongly associated with system A transporters. Physiological impairment of SNAT proteins reduced the antibody-initiated effector phase of arthritis, mainly by affecting the levels of circulating monocytes and neutrophils. MeAIB was also shown to affect the proliferation of immortalized cells, through trans-inhibition of SNAT proteins. Based on our observations, we conclude that SNAT proteins regulate the initial stages of lymphocyte activation by regulating glutamine uptake, and that the effector phase of arthritis can be affected by non-metabolized SNAT substrates. Most probably, metabolically active cells within both the adaptive and the innate immune systems are regulated by SNAT proteins and play a role in modifying arthritis development. © 2015 John Wiley & Sons Ltd.
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