Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0003873 (rheumatoid arthritis)
 53,068 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Genetic predisposition to rheumatoid arthritis (RA) is linked to the MHC class II allele HLA-DR4. The charge of the amino acid at DRbeta71 in the peptide-binding site appears to be critical in discriminating DR molecules linked to increased disease susceptibility. We have determined the 2.5 A x-ray structure of the DR4 molecule with the strongest linkage to RA (DRB1*0401) complexed with a human collagen II peptide. Details of a predicted salt bridge between lysine DRbeta71 and aspartic acid at the P4 peptide position suggest how it may participate in both antigen binding and TCR activation. A model is proposed for the DR4 recognition of collagen II (261-273), an antigen immunodominant in human-transgenic mouse models of RA.
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PMID:X-ray crystal structure of HLA-DR4 (DRA*0101, DRB1*0401) complexed with a peptide from human collagen II. 935 68

Stromelysin-1 (MMP-3) is an important member of the matrix metalloproteinase family. In joint-degrading diseases like arthritis, elevated levels of MMP-3 protein are detected in synovial fluid using immunological methods. However, these methods do not discriminate between active and inactive enzyme. In the present study, a specific stromelysin activity assay was developed using the selective fluorogenic substrate TNO003 (Dabcyl-Gaba-Arg-Pro-Lys-Pro-Val-Glu / Nva-Trp-Arg-Glu-(EDANS)-Ala-Lys-NH2, / =cleavage site). For its use in biological media, cleavage of TNO003 by enzymes other than stromelysin was effectively blocked by a proteinase inhibitor cocktail. Spiking of MMP-3 to synovial fluid resulted in an MMP-3 concentration-dependent linear increase in activity. The measured MMP-3 activity was not affected by the addition of MMP-13, even in a 5-fold excess over MMP-3. Synovial fluid from rheumatoid arthritis patients demonstrated 100-fold higher levels of active stromelysin than control synovial fluids.
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PMID:Highly increased levels of active stromelysin in rheumatoid synovial fluid determined by a selective fluorogenic assay. 942 33

Rheumatoid arthritis (RA) is associated with the presence of particular HLA-DRB1 alleles. In order to characterize HLA-DQB1 and/or-DPB1 alleles that contribute to disease susceptibility besides HLA-DRB1 alleles, we have analysed the HLA-DRB1, -DQB1 and -DPB1 polymorphism in 84 RA patients and 135 controls. HLA typing for HLA-DRB1 and -DQB1 alleles was performed using sequence-specific primers in combination with sequence-based typing. HLA-DPB1 alleles were characterized by reverse dot-blot hybridization. Our data confirm the predominant role of the (Q)R/KRAA sequence from AA position 70-74 of the HLA-DRB chain for disease susceptibility. In particular, the lysine (K) substitution at position 71 was highly significantly associated with RA. Analysis of the DQB1 locus revealed no association with RA when linkage disequilibrium between HLA-DRB1 and -DQB1 alleles was considered. In contrast, we observed an increased frequency of HLA-DPB1*0401 among (Q)R/KRAA-positive patients. (Q)R/KRAA-negative RA patients exhibited an overrepresentation of HLA-DPB1*0201 and HLA-DPB1*0601. Rheumatoid factor (RF) production correlated with the presence of the disease-associated (Q)R/KRAA amino acid cassette of the HLA-DRB chain. When HLA-DPB1 allele frequencies were compared between RF-positive and RF-negative RA patients, we observed an increased frequency of HLA-DPB1*0401 among RF-positive RA patients and HLA-DPB1*0201 among RF-negative patients. These results suggest that besides the predominent role of HLA-DR molecules in RA, HLA-DP molecules may have an influence on disease susceptibility and could modulate disease progression. HLA-DPB1*0401 may function in addition to HLA-DRB1*04, whereas HLA-DPB1*0201 and -DPB1*0601 may represent additional risk factors among (Q)R/KRAA-negative RA patients.
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PMID:HLA-DR/DQ/DP interactions in rheumatoid arthritis. 944 4

Immunization of mice with type II collagen (CII) leads to collagen-induced arthritis (CIA), a model for rheumatoid arthritis. T cell recognition of CII is believed to be a critical step in CIA development. We have analyzed the T cell determinants on CII and the TCR used for their recognition, using twenty-nine T cell hybridomas derived from C3H.Q and DBA/1 mice immunized with rat CII. All hybridomas were specific for the CII(256-270) segment. However, posttranslational modifications (hydroxylation and variable O-linked glycosylation) of the lysine at position 264 generated five T cell determinants that were specifically recognized by different T cell hybridoma subsets. TCR sequencing indicated that each of the five T cell epitopes selected its own TCR repertoire. The physiological relevance of this observation was shown by in vivo antibody-driven depletion of TCR Valpha2-positive T cells, which resulted in an inhibition of the T cell proliferative response in vitro towards the non-modified CII(256-270), but not towards the glycosylated epitope. Most hybridomas (20/29) specifically recognized CII(256-270) glycosylated with a monosaccharide (beta-D-galactopyranose). We conclude that this glycopeptide is immunodominant in CIA and that posttranslational modifications of CII create new T cell determinants that generate a diverse TCR repertoire.
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PMID:Epitope glycosylation plays a critical role for T cell recognition of type II collagen in collagen-induced arthritis. 971 Feb 35

Copolymer 1 [poly(Y,E,A,K)] is a random synthetic amino acid copolymer of L-tyrosine, L-glutamic acid, L-alanine, and L-lysine that is effective both in suppression of experimental allergic encephalomyelitis and in the treatment of relapsing forms of multiple sclerosis. Copolymer 1 binds promiscuously and very efficiently to purified HLA-DR molecules within the peptide-binding groove. In the present study, YEAK and YEAK-related copolymers and type II collagen (CII) peptide 261-273, a candidate autoantigen in rheumatoid arthritis (RA), competed for binding to RA-associated HLA-DR molecules encoded by DRB1*0101 and DRB1*0401. Moreover, these copolymers (particularly YEAK, YAK, and YEK) inhibited the response of DR1- and DR4-restricted T cell clones to the CII epitope 261-273 by >50%. This direct evidence both for competitive interactions of these copolymers and CII peptide with RA-associated HLA-DR molecules and for inhibition of CII-specific T cell responses suggests that these compounds should be evaluated in animal models for rheumatoid arthritis.
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PMID:Synthetic amino acid copolymers that bind to HLA-DR proteins and inhibit type II collagen-reactive T cell clones. 977 May 19

Oxidative stress and oxidative damage to tissues are common end points of chronic diseases, such as atherosclerosis, diabetes, and rheumatoid arthritis. The question addressed in this review is whether increased oxidative stress has a primary role in the pathogenesis of diabetic complications or whether it is a secondary indicator of end-stage tissue damage in diabetes. The increase in glycoxidation and lipoxidation products in plasma and tissue proteins suggests that oxidative stress is increased in diabetes. However, some of these products, such as 3-deoxyglucosone adducts to lysine and arginine residues, are formed independent of oxidation chemistry. Elevated levels of oxidizable substrates may also explain the increase in glycoxidation and lipoxidation products in tissue proteins, without the necessity of invoking an increase in oxidative stress. Further, age-adjusted levels of oxidized amino acids, a more direct indicator of oxidative stress, are not increased in skin collagen in diabetes. We propose that the increased chemical modification of proteins by carbohydrates and lipids in diabetes is the result of overload on metabolic pathways involved in detoxification of reactive carbonyl species, leading to a general increase in steady-state levels of reactive carbonyl compounds formed by both oxidative and nonoxidative reactions. The increase in glycoxidation and lipoxidation of tissue proteins in diabetes may therefore be viewed as the result of increased carbonyl stress. The distinction between oxidative and carbonyl stress is discussed along with the therapeutic implications of this difference.
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PMID:Role of oxidative stress in diabetic complications: a new perspective on an old paradigm. 989 15

Oxidative stress is apparent in pathology associated with aging and many age-related, chronic diseases, including atherosclerosis, diabetes mellitus, rheumatoid arthritis, and neurodegenerative diseases. Although it cannot be measured directly in biological systems, several biomarkers have been identified that provide a measure of oxidative damage to biomolecules. These include amino acid oxidation products (methionine sulfoxide, ortho-tyrosine (o-tyr) and dityrosine, chlorotyrosine and nitrotyrosine), as well as chemical modifications of protein following carbohydrate or lipid oxidation, such as N epsilon-(carboxymethyl)lysine and N epsilon-(carboxyethyl)lysine, and malondialdehyde and 4-hydroxynonenal adducts to amino acids. Other biomarkers include the amino acid cross-link pentosidine, the imidazolone adducts formed by reaction of 3-deoxyglucosone or methylglyoxal with arginine, and the imidazolium cross-links formed by the reaction of glyoxal and methylglyoxal with lysine residues in protein. These compounds have been measured in short-lived intracellular proteins, plasma proteins, long-lived extracellular proteins, and in urine, making them valuable tools for monitoring tissue-specific and systemic chemical and oxidative damage to proteins in biological systems. They are normally measured by sensitive high-performance liquid chromatography or gas chromatography-mass spectrometry methods, requiring both complex analytical instrumentation and derivatization procedures. However, sensitive immunohistochemical and ELISA assays are now available for many of these biomarkers. Immunochemical assays should facilitate studies on the role of oxidative stress in aging and chronic disease and simplify the evaluation of therapeutic approaches for limiting oxidative damage in tissues and treating pathologies associated with aging and disease. In this article we summarize recent data and conclusions based on immunohistochemical and ELISA assays, emphasizing the strengths and limitations of the techniques.
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PMID:Immunohistochemical and ELISA assays for biomarkers of oxidative stress in aging and disease. 992 37

Hyperglycaemia and/or oxidative stress can cause IgG to be modified by advanced glycation end products (AGE). Three patients with aggressive rheumatoid arthritis (RA) and vasculitis are described who have high titres of IgM antibodies against AGE-modified IgG (IgM anti-IgG-AGE). Diabetics and randomly selected patients with rheumatic diseases, including 50 additional RA patients, were tested for IgM and IgA anti-IgG-AGE by ELISA. AGE-modified proteins were detected using the nitroblue tetrazolium (NBT) colorimetric method. The presence of Nepsilon (carboxymethyl) lysine, an AGE modification, was detected on IgG-AGE by immunoblotting. A total of 20/41 (49%) rheumatoid factor (RF)-positive RA patients tested had IgM anti-IgG-AGE antibodies, 4/12 (33%) RF-positive systemic lupus erythematosus (SLE) patients, 3/5 RF-positive patients with primary Sjogren's syndrome (SS), and 3/5 RF-positive diabetics. All patients with RF-negative RA, SLE, SS, osteoarthritis (24), spondyloarthritis (15), adult-onset Still's disease (8), diabetes (25) and healthy controls (20) were anti-IgG-AGE negative. RF and IgM anti-IgG-AGE appeared to be a linked response. The IgM anti-IgG-AGE, along with IgG-AGE, may contribute to the pathogenesis of RA.
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PMID:A new antibody in rheumatoid arthritis targeting glycated IgG: IgM anti-IgG-AGE. 997 55

The assay for the cross-linked carboxyterminal telopeptide of type I collagen (ICTP) has been shown to reflect increased type I collagen degradation in such pathological conditions as bone metastases and rheumatoid arthritis, but to be rather insensitive to the changes in physiological bone collagen turnover (e.g., induced by estrogen or bisphosphonate treatment). To determine the reasons for this discrepancy we localized the antigenic determinant recognized by the ICTP assay and studied the effects of two major osteoclastic proteinases, cathepsin K (EC 3.4.22.38) and matrix metalloproteinase-9 (MMP-9; gelatinase B; EC 3.4.24.35), on immunoreactivity. The antigenic determinant was shown to reside within the hydrophobic phenylalanine-rich regions of the carboxyterminal telopeptides of the two alpha1 chains of human type I collagen, situated between the triple helical domain and the lysine-derived trivalent cross-link. This conclusion was based on differences between the amino acid sequences and cross reactivities of the corresponding human and bovine antigens before and after proteolytic treatments with chymotrypsin. A trivalent cross-link is necessary for providing such a structure, because the divalently cross-linked and monomeric natural and synthetic peptides from the same region, but containing only one phenylalanine-rich sequence, showed poor immunoreaction. Recombinant human cathepsin K cleaved the trivalently cross-linked ICTP structure at two sites between the phenylalanine-rich region and the cross-link, destroying the reactivity with ICTP antibodies. On the contrary, the treatment of isolated ICTP by the matrix metalloproteinases MMP-9 (gelatinase B), MMP-1 (collagenase 1), or MMP-13 (collagenase 3) had no effect on the immunoreaction. Our results indicate that the increased circulating concentrations of ICTP found in several clinical situations are most likely produced by matrix metalloproteinases, whereas cathepsin K-mediated, osteoclastic bone resorption destroys ICTP antigenicity.
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PMID:Immunochemical characterization of assay for carboxyterminal telopeptide of human type I collagen: loss of antigenicity by treatment with cathepsin K. 1071 80

The three major histocompatibility complex (MHC)-linked hsp70s have been screened for variation in their 28 kDa C-terminal regions by direct nucleotide sequencing of the corresponding DNA fragments. No amino acid variation was detected in the major heat-inducible hsp70 (encoded by hsp70-1 and hsp70-2), although previously unreported silent mutations were identified in all three of the MHC-linked hsp70 genes. A novel coding polymorphism, a G to A transition, was identified at nucleotide 2763 of hsp70-hom (hom-2763). This dimorphism results in a glutamic acid to lysine alteration at position 602 in the C-terminal domain of hsp70-hom. The frequencies of the A-2763 and G-2763 alleles were calculated to be 27% and 73%, respectively. The hom-2763 dimorphism was characterised in 81 HLA-homozygous cell lines using an ARMS-PCR assay and A-2763 was found to be in strong linkage disequilibrium with DRB1*04 (Pc=1.31 x 10(-7), following Bonferoni's correction). Analysis of 60 rheumatoid arthritis (RA) families, each with an affected sib-pair, revealed an association between hsp70-hom A-2763 and RA using both the transmission disequilibrium test (TDT) and the transmission to sib-pair (Tsp) test (P=0.0038 and P=0.013, respectively). This association may be due to linkage disequilibrium with HLA-DR alleles, but could represent an additional risk factor for RA in the MHC class III region.
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PMID:A novel variant of the MHC-linked hsp70, hsp70-hom, is associated with rheumatoid arthritis. 1095 54


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