Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0024141 (systemic lupus erythematosus)
 44,322 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interleukin-10 is a predominantly anti-inflammatory cytokine that inhibits macrophage and dendritic cell function, but can acquire proinflammatory activity during immune responses. We investigated whether type I IFNs, which are elevated during infections and in autoimmune diseases, modulate the activity of IL-10. Priming of primary human macrophages with low concentrations of IFN-alpha diminished the ability of IL-10 to suppress TNF-alpha production. IFN-alpha conferred a proinflammatory gain of function on IL-10, leading to IL-10 activation of expression of IFN-gamma-inducible, STAT1-dependent genes such as IFN regulatory factor 1, IFN-gamma-inducible protein-10 (CXCL10), and monokine induced by IFN-gamma (CXCL9). IFN-alpha priming resulted in greatly enhanced STAT1 activation in response to IL-10, and STAT1 was required for IL-10 activation of IFN-gamma-inducible protein-10 and monokine induced by IFN-gamma expression in IFN-alpha-primed cells. In control, unprimed cells, IL-10 activation of STAT1 was suppressed by constitutive activity of protein kinase C and Src homology 2 domain-containing phosphatase 1. These results demonstrate that type I IFNs regulate the balance between IL-10 anti- and proinflammatory activity, and provide insight into molecular mechanisms that regulate IL-10 function. Gain of IL-10 proinflammatory functions may contribute to its pathogenic role in autoimmune diseases characterized by elevated type I IFN levels, such as systemic lupus erythematosus.
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PMID:IFN-alpha priming results in a gain of proinflammatory function by IL-10: implications for systemic lupus erythematosus pathogenesis. 1512 40

The lymphoid-specific phosphatase (LYP) encoded by PTPN22 is involved in preventing spontaneous T-cell activation by dephosphorylating and inactivating T-cell receptor-associated Csk kinase. We have genotyped 396 type 1 diabetic patients and 1,178 control subjects of Caucasian descent from north central Florida and report a strong association between type 1 diabetes and a polymorphism (R620W) in the PTPN22 gene. The homozygous genotype for the T allele encoding the 620W residue is associated with an increased risk for developing type 1 diabetes (odds ratio [OR] = 3.4, P < 0.008), and the heterozygous genotype C/T had an OR of 1.7 (P = 6 x 10(-6)). The C/C homozygous genotype is protective against type 1 diabetes (OR = 0.5, P = 6 x 10(-6)). Furthermore, transmission disequilibrium analysis of 410 affected sibpair and simplex families of Caucasian descent indicated that the type 1 diabetes-associated T allele is transmitted more often (57.2%) than randomly expected (P < 0.003). Together with previous reports of the association between PTPN22 and type 1 diabetes, as well as rheumatoid arthritis and systemic lupus erythematosus, these results provide compelling evidence that LYP is a critical player in multiple autoimmune disorders.
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PMID:Genetic association between a lymphoid tyrosine phosphatase (PTPN22) and type 1 diabetes. 1573 72

A male patient receiving azathioprine treatment for discoid lupus erythematodes developed severe cholestatic hepatitis between 14 and 21 days after initiation of the treatment with peak bilirubin levels of 62.4 mg/dL. Other causes of hepatic dysfunction including viral hepatitis were clinically and serologically excluded. Liver biopsy revealed cholestatic hepatocellular damage. At 14 days after discontinuation of azathioprine the liver function (transaminases and bilirubin) began to improve. Only alcaline phosphatase and gamma-glutamyl transferase remained elevated even after 4 months. This case argues for an idiosyncratic cholestatic hepatocellular damage caused by azathioprine.
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PMID:Severe cholestatic hepatitis caused by azathioprine. 1580 61

Signaling of the C3a anaphylatoxin through its G protein-coupled receptor, C3aR, is relevant in a variety of inflammatory diseases, but its role in lupus nephritis is undefined. In this study, we show that expression of C3aR was significantly increased in prediseased and diseased kidneys of MRL/lpr lupus mice compared with MRL/+ controls. To investigate the role of C3aR in experimental lupus, a small molecule antagonist of C3aR (C3aRa) was administered continuously to MRL/lpr mice from 13 to 19 wk of age. All 13 C3aRa-treated mice survived during the 6-wk treatment compared with 9 of 14 (64.3%) control animals given vehicle (p = 0.019). Relative to controls, C3aRa-treated animals were protected from renal disease as measured by albuminuria (p = 0.040) and blood urea nitrogen (p = 0.021). In addition, there were fewer neutrophils, monocytes, and apoptotic cells in the kidneys of C3aRa-treated mice. C3aRa treatment also led to reduced renal IL-1beta and RANTES mRNA and phosphorylated phosphatase and tensin homologue deleted on chromosome 10 protein, whereas the mass of phosphorylated protein kinase B/Akt was increased by C3aRa. Thus, C3aR antagonism significantly reduces renal disease in MRL/lpr mice, which further translates into prolonged survival. These data illustrate that C3aR is relevant in experimental lupus nephritis and may be a target for therapeutic intervention in the human disease.
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PMID:Signaling through up-regulated C3a receptor is key to the development of experimental lupus nephritis. 1603 39

The gene PTPN22 is located on chromosome 1p13 and encodes a protein tyrosine phosphatase called the lymphoid-specific phosphatase (Lyp). Lyp is expressed in lymphocytes, where it physically associates through its proline-rich motif (called P1) with the SH3 domain of the protein tyrosine kinase Csk, an important suppressor of the Src family of kinases Lck and Fyn, which mediate TCR signaling. Therefore, it is said that interaction between Lyp and Csk enables these effectors to inhibit T-cell activation synergistically. It was reported that a missense single nucleotide polymorphism , R620W (rs2476601), 1858C->T encodes an amino-acid change in the P1 proline-rich motif of the gene PTPN22 and is associated with SLE in North American white individuals. PTPN22 gene polymorphisms were genotyped in 571 Swedish SLE patients and 1042 healthy controls using TaqMan SNP Genotyping Assay. Differences were observed between cases and control subjects at both the allele (chi(2)=11.2895;P=0.0007,1df) and genotype (chi(2)=10.2243;P=0.0013, 1df) levels. We also found evidence of a genetic association between PTPN22 and renal disorder (chi(2)=9.5660;P=0.0019). We then analyzed if in patients with renal disorder associations with PDCD1 and PTPN22 were independent. Our data suggest that this appears to be the case although we observed some degree of interaction.
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PMID:The R620W C/T polymorphism of the gene PTPN22 is associated with SLE independently of the association of PDCD1. 1605 72

The B cell inhibitory receptor FcgammaRIIB plays crucial roles in the maintenance of self-tolerance. We have identified a polymorphism FCGR2B c.695T>C that results in the non-conservative replacement of 232Ile at the transmembrane helix to Thr and demonstrated the association of the polymorphism with susceptibility to systemic lupus erythematosus (SLE) in Asians. In this study, we examined the impact of FCGR2B c.695T>C on the functional properties of FcgammaRIIB by expressing each allele product in a human B cell line ST486 lacking endogenous FcgammaRIIB. FcgammaRIIB 232Thr was found to be significantly less potent than wild-type 232Ile in inhibiting B cell receptor (BCR)-mediated phosphatidylinositol-3,4,5-trisphosphate accumulation, Akt and PLCgamma2 activation and calcium mobilization, and to display decreased levels of tyrosine phosphorylation and SH2-containing 5'-inositolphosphate phosphatase recruitment compared with 232Ile after IgG Fc-mediated coligation with BCR. Notably, a quantitative analysis of the subcellular distribution of FcgammaRIIB using 125I-labeled anti-FcgammaRIIB revealed that FcgammaRIIB 232Thr is less effectively distributed to detergent-insoluble lipid rafts than 232Ile, findings in accordance with the importance of the transmembrane amino acid residues, in particular large hydrophobic amino acids including Ile, in the association of membrane proteins with lipid rafts. Given the crucial roles of lipid rafts in integrating BCR signaling, decreased association of FcgammaRIIB 232Thr could contribute to its impaired inhibitory potential. Collectively, the present findings indicate that the Ile232Thr substitution affects the localization and function of FcgammaRIIB and that the molecular mechanism may link the polymorphism and susceptibility to SLE.
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PMID:FcgammaRIIB Ile232Thr transmembrane polymorphism associated with human systemic lupus erythematosus decreases affinity to lipid rafts and attenuates inhibitory effects on B cell receptor signaling. 1611 11

A functional single nucleotide polymorphism (SNP) C1858T in the protein tyrosine phosphatase nonreceptor 22 (PTPN22) gene encoding an intracellular phosphatase with negative regulatory effects on T-cell activation is associated with some autoimmune diseases in Caucasians. Taking into account firstly, that SNP frequencies may vary across populations and, secondly, that replication studies are important to confirm previous associations, we examined the influence of PTPN22 polymorphism in 621 Colombian patients with four autoimmune diseases. Accordingly, 298 patients with rheumatoid arthritis (RA), 143 with systemic lupus erythematosus (SLE), 70 with primary Sjogren's syndrome (pSS) and 110 with Type 1 diabetes (T1D) were studied. The control group consisted of 308 matched healthy individuals. Genotyping of PTPN22 was performed by the real-time polymerase chain reaction technology, using the Taq Man 5'-allele discrimination assay. The 1858 T allele was found to be a risk factor for pSS (odds ratio (OR)=2.42), SLE (OR=2.56), and T1D (OR=1.83). A lower but nonsignificant trend was observed for RA (OR=1.26). These results confirm the influence of PTPN22 in autoimmunity and indicate that autoimmune phenotypes could represent pleiotropic outcomes of nonspecific disease genes that underlie similar immunogenetic mechanisms.
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PMID:PTPN22 C1858T polymorphism in Colombian patients with autoimmune diseases. 1616 73

A SNP in the gene PTPN22 is associated with type 1 diabetes, rheumatoid arthritis, lupus, Graves thyroiditis, Addison disease and other autoimmune disorders. T cells from carriers of the predisposing allele produce less interleukin-2 upon TCR stimulation, and the encoded phosphatase has higher catalytic activity and is a more potent negative regulator of T lymphocyte activation. We conclude that the autoimmune-predisposing allele is a gain-of-function mutant.
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PMID:Autoimmune-associated lymphoid tyrosine phosphatase is a gain-of-function variant. 1631 59

We recently discovered that a single-nucleotide polymorphism (SNP) in the lymphoid tyrosine phosphatase (LYP), encoded by the PTPN22 gene on chromosome 1p13, correlates strongly with the incidence of type 1 diabetes (T1D) in two independent populations. This findings has now been verified by numerous studies and it has been expanded to rheumatoid arthritis, juvenile rheumatoid arthritis, systemic lupus erythematosus, Graves' disease, generalized vitiligo and other autoimmune disease. Here we review the genetics of the SNP and its association with autoimmunity, discuss the function of the phosphatase in signaling, the biochemistry of the disease-predisposing allele, and the possible mechanisms by which PTPN22 contributes to the development of human disease.
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PMID:Role of PTPN22 in type 1 diabetes and other autoimmune diseases. 1669 61

A functional polymorphism in PTPN22, a gene encoding a phosphatase involved in T-cell signaling, has been associated with autoimmunity. We checked for the prevalence of the PTPN22 R620W polymorphism in multiplex families affected with systemic lupus erythematosus (SLE) and other autoimmune diseases. Its association with other polymorphisms in mannose binding lectin (MBL) and FcgammaRIIa (CD32A) genes was also studied. Deoxyribonucleic acid samples were obtained from 233 Spanish individuals who belonged to 21 families in which at least two members had been diagnosed with some autoimmune disease, mainly SLE. A healthy control population was also included (n= 129). Genotyping for the R620W single-nucleotide polymorphism (SNP) was performed by restriction fragment length polymorphism analysis of polymerase chain reaction products. Allele frequency for the T allele was slightly higher in the families with autoimmune disease, especially when considering the affected individuals (0.094 vs 0.062). Actually, 18.8% affected family members vs 11.6% controls had the polymorphism (P= 0.179). Nineteen percent of affected individuals had both the PTPN22 T and the CD32A R131 alleles, whereas only 8.5% unaffected relatives had both susceptibility alleles simultaneously [P= 0.031, odds ratios 2.508 (95% confidence interval 1.066-5.896)]. The tendency toward finding the T allele more frequently in members affected with some particular autoimmune disorder suggests that this SNP may confer susceptibility to autoimmunity. The fact that more affected than unaffected relatives carried both the T and the R131 alleles simultaneously leads us to think about the existence of a combinatorial effect between genes that could help define individuals prone to autoimmune diseases.
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PMID:Multiplex family-based study in systemic lupus erythematosus: association between the R620W polymorphism of PTPN22 and the FcgammaRIIa (CD32A) R131 allele. 1709 57


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