RESUMO
Sarcoidosis is a complex disease of unknown etiology characterized by the presence of granulomatous inflammation. Though various immune system pathways have been implicated in disease, the relationship between the genetic determinants of sarcoidosis and other inflammatory disorders has not been characterized. Herein, we examined the degree of genetic pleiotropy common to sarcoidosis and other inflammatory disorders to identify shared pathways and disease systems pertinent to sarcoidosis onset. To achieve this, we quantify the association of common variant polygenic risk scores from nine complex inflammatory disorders with sarcoidosis risk. Enrichment analyses of genes implicated in pleiotropic associations were further used to elucidate candidate pathways. In European-Americans, we identify significant pleiotropy between risk of sarcoidosis and risk of asthma (R2=2.03%; P=8.89 × 10-9), celiac disease (R2=2.03%; P=8.21 × 10-9), primary biliary cirrhosis (R2=2.43%; P=2.01 × 10-10) and rheumatoid arthritis (R2=4.32%; P=2.50 × 10-17). These associations validate in African Americans only after accounting for the proportion of genome-wide European ancestry, where we demonstrate similar effects of polygenic risk for African-Americans with the highest levels of European ancestry. Variants and genes implicated in European-American pleiotropic associations were enriched for pathways involving interleukin-12, interleukin-27 and cell adhesion molecules, corroborating the hypothesized immunopathogenesis of disease.
Assuntos
Pleiotropia Genética , Inflamação/genética , Sarcoidose/genética , Negro ou Afro-Americano/genética , Humanos , Inflamação/imunologia , Interleucina-12/imunologia , Interleucinas/imunologia , Herança Multifatorial , Sarcoidose/imunologia , População Branca/genéticaRESUMO
Linkage disequilibrium poses a major challenge to the functional characterization of specific disease-associated susceptibility variants. Precision genome-editing technologies have provided new opportunities to address this challenge. As proof of concept, we employed TALEN (transcription activation-like effector nuclease)-mediated genome editing to specifically disrupt the TT>A enhancer region to mimic candidate causal variants identified in the systemic lupus erythematosus-associated susceptibility gene, tumor necrosis factor-α-induced protein 3 (TNFAIP3), in an isogenic HEK293T cell line devoid of other linkage disequilibrium-associated variants. Targeted disruption of the TT>A enhancer impaired its interaction with the TNFAIP3 promoter by long-range DNA looping, thereby reducing TNFAIP3 gene expression. Loss of TNFAIP3 mRNA and its encoded protein, A20, impaired tumor necrosis factor-α-induced receptor-mediated downregulation of nuclear factor-κB signaling, a hallmark of autoimmunity. Results demonstrate that the TT>A enhancer variants contribute to causality and function independently of other variants to disrupt TNFAIP3 expression. Furthermore, we believe this approach can be implemented to independently examine other candidate casual variants in the future.
Assuntos
Elementos Facilitadores Genéticos , Lúpus Eritematoso Sistêmico/genética , Mutação , Fenótipo , Proteína 3 Induzida por Fator de Necrose Tumoral alfa/genética , Regulação para Baixo , Células HEK293 , Humanos , NF-kappa B/metabolismo , Polimorfismo de Nucleotídeo Único , Regiões Promotoras Genéticas , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transdução de Sinais , Proteína 3 Induzida por Fator de Necrose Tumoral alfa/metabolismoRESUMO
Systemic amyloid A (AA) amyloidosis is highly prevalent (34%) in endangered island foxes (Urocyon littoralis) and poses a risk to species recovery. Although elevated serum AA (SAA) from prolonged or recurrent inflammation predisposes to AA amyloidosis, additional risk factors are poorly understood. Here we define the severity of glomerular and medullary renal amyloid and identify risk factors for AA amyloidosis in 321 island foxes necropsied from 1987 through 2010. In affected kidneys, amyloid more commonly accumulated in the medullary interstitium than in the glomeruli (98% [n= 78 of 80] vs 56% [n= 45], respectively;P< .0001), and medullary deposition was more commonly severe (19% [n= 20 of 105]) as compared with glomeruli (7% [n= 7];P= .01). Univariate odds ratios (ORs) of severe renal AA amyloidosis were greater for short- and long-term captive foxes as compared with free-ranging foxes (ORs = 3.2, 3.7, respectively; overall P= .05) and for females as compared with males (OR = 2.9;P= .05). Multivariable logistic regression revealed that independent risk factors for amyloid development were increasing age class (OR = 3.8;P< .0001), San Clemente Island subspecies versus San Nicolas Island subspecies (OR = 5.3;P= .0003), captivity (OR = 5.1;P= .0001), and nephritis (OR = 2.3;P= .01). The increased risk associated with the San Clemente subspecies or captivity suggests roles for genetic as well as exogenous risk factors in the development of AA amyloidosis.
Assuntos
Amiloidose/veterinária , Raposas , Nefrite/veterinária , Proteína Amiloide A Sérica/metabolismo , Amiloidose/epidemiologia , Amiloidose/metabolismo , Amiloidose/patologia , Animais , Espécies em Perigo de Extinção , Feminino , Inflamação/veterinária , Rim/metabolismo , Modelos Logísticos , Masculino , Nefrite/epidemiologia , Nefrite/metabolismo , Nefrite/patologia , Fatores de Risco , Índice de Gravidade de DoençaRESUMO
A classic T-cell phenotype in systemic lupus erythematosus (SLE) is the downregulation and replacement of the CD3ζ chain that alters T-cell receptor signaling. However, genetic associations with SLE in the human CD247 locus that encodes CD3ζ are not well established and require replication in independent cohorts. Our aim was therefore to examine, localize and validate CD247-SLE association in a large multiethnic population. We typed 44 contiguous CD247 single-nucleotide polymorphisms (SNPs) in 8922 SLE patients and 8077 controls from four ethnically distinct populations. The strongest associations were found in the Asian population (11 SNPs in intron 1, 4.99 × 10(-4) < P < 4.15 × 10(-2)), where we further identified a five-marker haplotype (rs12141731-rs2949655-rs16859085-rs12144621-rs858554; G-G-A-G-A; P(hap) = 2.12 × 10(-5)) that exceeded the most associated single SNP rs858554 (minor allele frequency in controls = 13%; P = 4.99 × 10(-4), odds ratio = 1.32) in significance. Imputation and subsequent association analysis showed evidence of association (P < 0.05) at 27 additional SNPs within intron 1. Cross-ethnic meta-analysis, assuming an additive genetic model adjusted for population proportions, showed five SNPs with significant P-values (1.40 × 10(-3) < P< 3.97 × 10(-2)), with one (rs704848) remaining significant after Bonferroni correction (P(meta) = 2.66 × 10(-2)). Our study independently confirms and extends the association of SLE with CD247, which is shared by various autoimmune disorders and supports a common T-cell-mediated mechanism.
Assuntos
Complexo CD3/genética , Lúpus Eritematoso Sistêmico/etnologia , Lúpus Eritematoso Sistêmico/genética , Adulto , Povo Asiático/genética , Estudos de Casos e Controles , Feminino , Estudos de Associação Genética , Predisposição Genética para Doença , Haplótipos , Humanos , Masculino , Polimorfismo de Nucleotídeo Único , Linfócitos T/imunologia , População Branca/genéticaRESUMO
In a genome-wide association study (GWAS) of individuals of European ancestry afflicted with systemic lupus erythematosus (SLE) the extensive utilization of imputation, step-wise multiple regression, lasso regularization and increasing study power by utilizing false discovery rate instead of a Bonferroni multiple test correction enabled us to identify 13 novel non-human leukocyte antigen (HLA) genes and confirmed the association of four genes previously reported to be associated. Novel genes associated with SLE susceptibility included two transcription factors (EHF and MED1), two components of the NF-κB pathway (RASSF2 and RNF114), one gene involved in adhesion and endothelial migration (CNTN6) and two genes involved in antigen presentation (BIN1 and SEC61G). In addition, the strongly significant association of multiple single-nucleotide polymorphisms (SNPs) in the HLA region was assigned to HLA alleles and serotypes and deconvoluted into four primary signals. The novel SLE-associated genes point to new directions for both the diagnosis and treatment of this debilitating autoimmune disease.
Assuntos
Predisposição Genética para Doença/genética , Estudo de Associação Genômica Ampla/métodos , Antígenos HLA/genética , Lúpus Eritematoso Sistêmico/genética , Polimorfismo de Nucleotídeo Único , Feminino , Frequência do Gene , Genótipo , Haplótipos , Humanos , Modelos Logísticos , Análise de Componente PrincipalRESUMO
Systemic lupus erythematosus (SLE) is a clinically heterogeneous disease affecting multiple organ systems and characterized by autoantibody formation to nuclear components. Although genetic variation within the major histocompatibility complex (MHC) is associated with SLE, its role in the development of clinical manifestations and autoantibody production is not well defined. We conducted a meta-analysis of four independent European SLE case collections for associations between SLE sub-phenotypes and MHC single-nucleotide polymorphism genotypes, human leukocyte antigen (HLA) alleles and variant HLA amino acids. Of the 11 American College of Rheumatology criteria and 7 autoantibody sub-phenotypes examined, anti-Ro/SSA and anti-La/SSB antibody subsets exhibited the highest number and most statistically significant associations. HLA-DRB1*03:01 was significantly associated with both sub-phenotypes. We found evidence of associations independent of MHC class II variants in the anti-Ro subset alone. Conditional analyses showed that anti-Ro and anti-La subsets are independently associated with HLA-DRB1*0301, and that the HLA-DRB1*03:01 association with SLE is largely but not completely driven by the association of this allele with these sub-phenotypes. Our results provide strong evidence for a multilevel risk model for HLA-DRB1*03:01 in SLE, where the association with anti-Ro and anti-La antibody-positive SLE is much stronger than SLE without these autoantibodies.
Assuntos
Autoanticorpos , Cadeias HLA-DRB1 , Lúpus Eritematoso Sistêmico/genética , Modelos Genéticos , Autoanticorpos/genética , Autoanticorpos/imunologia , Europa (Continente) , Feminino , Cadeias HLA-DRB1/genética , Cadeias HLA-DRB1/imunologia , Humanos , Lúpus Eritematoso Sistêmico/imunologia , MasculinoAssuntos
Aborto Espontâneo , Apoio Social , Natimorto , Feminino , Humanos , Gravidez , Inquéritos e QuestionáriosRESUMO
Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by autoantibody production and organ damage. Lupus nephritis (LN) is one of the most severe manifestations of SLE. Multiple studies reported associations between renal diseases and variants in the non-muscle myosin heavy chain 9 (MYH9) and the neighboring apolipoprotein L 1 (APOL1) genes. We evaluated 167 variants spanning MYH9 for association with LN in a multiethnic sample. The two previously identified risk variants in APOL1 were also tested for association with LN in European-Americans (EAs) (N = 579) and African-Americans (AAs) (N = 407). Multiple peaks of association exceeding a Bonferroni corrected P-value of P < 2.03 × 10(-3) were observed between LN and MYH9 in EAs (N = 4620), with the most pronounced association at rs2157257 (P = 4.7 × 10(-4), odds ratio (OR) = 1.205). A modest effect with MYH9 was also detected in Gullah (rs8136069, P = 0.0019, OR = 2.304). No association between LN and MYH9 was found in AAs, Asians, Amerindians or Hispanics. This study provides the first investigation of MYH9 in LN in non-Africans and of APOL1 in LN in any population, and presents novel insight into the potential role of MYH9 in LN in EAs.
Assuntos
Apolipoproteínas/genética , Negro ou Afro-Americano/genética , Lipoproteínas HDL/genética , Nefrite Lúpica/etnologia , Nefrite Lúpica/genética , Proteínas Motores Moleculares/genética , Cadeias Pesadas de Miosina/genética , Apolipoproteína L1 , Predisposição Genética para Doença , Humanos , Desequilíbrio de Ligação , Polimorfismo de Nucleotídeo Único , População Branca/genéticaRESUMO
Systemic lupus erythematosus (SLE) is an autoimmune disease with diverse clinical manifestations characterized by the development of pathogenic autoantibodies manifesting in inflammation of target organs such as the kidneys, skin and joints. Genome-wide association studies have identified genetic variants in the UBE2L3 region that are associated with SLE in subjects of European and Asian ancestry. UBE2L3 encodes an ubiquitin-conjugating enzyme, UBCH7, involved in cell proliferation and immune function. In this study, we sought to further characterize the genetic association in the region of UBE2L3 and use molecular methods to determine the functional effect of the risk haplotype. We identified significant associations between variants in the region of UBE2L3 and SLE in individuals of European and Asian ancestry that exceeded a Bonferroni-corrected threshold (P<1 × 10(-4)). A single risk haplotype was observed in all associated populations. Individuals harboring the risk haplotype display a significant increase in both UBE2L3 mRNA expression (P=0.0004) and UBCH7 protein expression (P=0.0068). The results suggest that variants carried on the SLE-associated UBE2L3 risk haplotype influence autoimmunity by modulating UBCH7 expression.
Assuntos
Predisposição Genética para Doença , Haplótipos , Lúpus Eritematoso Sistêmico/genética , Enzimas de Conjugação de Ubiquitina/genética , Negro ou Afro-Americano/genética , Alelos , Povo Asiático/genética , Feminino , Hispânico ou Latino/genética , Humanos , Desequilíbrio de Ligação , Lúpus Eritematoso Sistêmico/etnologia , Masculino , Polimorfismo de Nucleotídeo Único , Enzimas de Conjugação de Ubiquitina/metabolismo , População Branca/genéticaRESUMO
OBJECTIVES: Homozygous C1q deficiency is an extremely rare condition and strongly associated with systemic lupus erythematosus. To assess and characterize C1q deficiency in an African-American lupus pedigree, C1q genomic region was evaluated in the lupus cases and family members. METHODS: Genomic DNA from patient was obtained and C1q A, B and C gene cluster was sequenced using next generation sequencing method. The identified mutation was further confirmed by direct Sanger sequencing method in the patient and all blood relatives. C1q levels in serum were measured using sandwich ELISA method. RESULTS: In an African-American patient with lupus and C1q deficiency, we identified and confirmed a novel homozygote start codon mutation in C1qA gene that changes amino acid methionine to arginine at position 1. The Met1Arg mutation prevents protein translation (Met1Arg). Mutation analyses of the patient's family members also revealed the Met1Arg homozygote mutation in her deceased brother who also had lupus with absence of total complement activity consistent with a recessive pattern of inheritance. CONCLUSION: The identification of new mutation in C1qA gene that disrupts the start codon (ATG to AGG (Met1Arg)) has not been reported previously and it expands the knowledge and importance of the C1q gene in the pathogenesis of lupus especially in the high-risk African-American population.
Assuntos
Complemento C1q/deficiência , Complemento C1q/genética , Lúpus Eritematoso Sistêmico/sangue , Lúpus Eritematoso Sistêmico/genética , Mutação Puntual , Adulto , Negro ou Afro-Americano/genética , Substituição de Aminoácidos , Sequência de Bases , Códon de Iniciação/genética , Análise Mutacional de DNA , Feminino , Genes Recessivos , Homozigoto , Humanos , Masculino , Linhagem , Adulto JovemRESUMO
The major histocompatibility complex (MHC) class II transactivator gene (CIITA) encodes an important transcription factor required for human leukocyte antigens (HLA) class II MHC-restricted antigen presentation. MHC genes, including the HLA class II DRB1*03:01 allele, are strongly associated with systemic lupus erythematosus (SLE). Recently the rs4774 CIITA missense variant (+1632G/C) was reported to be associated with susceptibility to multiple sclerosis. In the current study, we investigated CIITA, DRB1*03:01 and risk of SLE using a multi-stage analysis. In stage 1, 9 CIITA variants were tested in 658 cases and 1363 controls (N=2021). In stage 2, rs4774 was tested in 684 cases and 2938 controls (N=3622). We also performed a meta-analysis of the pooled 1342 cases and 4301 controls (N=5643). In stage 1, rs4774(*)C was associated with SLE (odds ratio (OR)=1.24, 95% confidence interval (95% CI)=1.07-1.44, P=4.2 × 10(-3)). Similar results were observed in stage 2 (OR=1.16, 95% CI=1.02-1.33, P=8.5 × 10(-3)) and the meta-analysis of the combined data set (OR=1.20, 95% CI=1.09-1.33, P(meta)=2.5 × 10(-4)). In all three analyses, the strongest evidence for association between rs4774(*)C and SLE was present in individuals who carried at least one copy of DRB1*03:01 (P(meta)=1.9 × 10(-3)). Results support a role for CIITA in SLE, which appears to be stronger in the presence of DRB1*03:01.
Assuntos
Predisposição Genética para Doença , Lúpus Eritematoso Sistêmico/genética , Mutação de Sentido Incorreto , Proteínas Nucleares/genética , Transativadores/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Alelos , Feminino , Cadeias HLA-DRB1/genética , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Risco , Adulto JovemRESUMO
Systemic lupus erythematosus (SLE) is a prototypic autoimmune disorder with a complex pathogenesis in which genetic, hormonal and environmental factors have a role. Rare mutations in the TREX1 gene, the major mammalian 3'-5' exonuclease, have been reported in sporadic SLE cases. Some of these mutations have also been identified in a rare pediatric neurological condition featuring an inflammatory encephalopathy known as Aicardi-Goutières syndrome (AGS). We sought to investigate the frequency of these mutations in a large multi-ancestral cohort of SLE cases and controls. A total of 40 single-nucleotide polymorphisms (SNPs), including both common and rare variants, across the TREX1 gene, were evaluated in â¼8370 patients with SLE and â¼7490 control subjects. Stringent quality control procedures were applied, and principal components and admixture proportions were calculated to identify outliers for removal from analysis. Population-based case-control association analyses were performed. P-values, false-discovery rate q values, and odds ratios (OR) with 95% confidence intervals (CI) were calculated. The estimated frequency of TREX1 mutations in our lupus cohort was 0.5%. Five heterozygous mutations were detected at the Y305C polymorphism in European lupus cases but none were observed in European controls. Five African cases incurred heterozygous mutations at the E266G polymorphism and, again, none were observed in the African controls. A rare homozygous R114H mutation was identified in one Asian SLE patient, whereas all genotypes at this mutation in previous reports for SLE were heterozygous. Analysis of common TREX1 SNPs (minor allele frequency (MAF)>10%) revealed a relatively common risk haplotype in European SLE patients with neurological manifestations, especially seizures, with a frequency of 58% in lupus cases compared with 45% in normal controls (P=0.0008, OR=1.73, 95% CI=1.25-2.39). Finally, the presence or absence of specific autoantibodies in certain populations produced significant genetic associations. For example, a strong association with anti-nRNP was observed in the European cohort at a coding synonymous variant rs56203834 (P=2.99E-13, OR=5.2, 95% CI=3.18-8.56). Our data confirm and expand previous reports and provide additional support for the involvement of TREX1 in lupus pathogenesis.
Assuntos
Exodesoxirribonucleases/genética , Lúpus Eritematoso Sistêmico/genética , Fosfoproteínas/genética , Estudos de Coortes , Feminino , Haplótipos , Humanos , Lúpus Eritematoso Sistêmico/epidemiologia , Masculino , Mutação , Fenótipo , Polimorfismo de Nucleotídeo ÚnicoRESUMO
The production of reactive oxygen species (ROS) by neutrophils has a vital role in defence against a range of infectious agents, and is driven by the assembly of a multi-protein complex containing a minimal core of five proteins: the two membrane-bound subunits of cytochrome b(558) (gp91(phox) and p22(phox)) and three soluble factors (GTP-Rac, p47(phox) and p67(phox) (refs 1, 2). This minimal complex can reconstitute ROS formation in vitro in the presence of non-physiological amphiphiles such as SDS. p40(phox) has subsequently been discovered as a binding partner for p67(phox) (ref. 3), but its role in ROS formation is unclear. Phosphoinositide-3-OH kinases (PI(3)Ks) have been implicated in the intracellular signalling pathways coordinating ROS formation but through an unknown mechanism. We show that the addition of p40(phox) to the minimal core complex allows a lipid product of PI(3)Ks, phosphatidylinositol 3-phosphate (PtdIns(3)P), to stimulate specifically the formation of ROS. This effect was mediated by binding of PtdIns(3)P to the PX domain of p40(phox). These results offer new insights into the roles for PI(3)Ks and p40(phox) in ROS formation and define a cellular ligand for the orphan PX domain.
Assuntos
Neutrófilos/enzimologia , Oxirredutases/sangue , Oxirredutases/efeitos dos fármacos , Fosfatos de Fosfatidilinositol/farmacologia , Fosfoproteínas/metabolismo , Animais , Sítios de Ligação , Grupo dos Citocromos b/efeitos dos fármacos , Grupo dos Citocromos b/metabolismo , Membranas Artificiais , Oxirredução , Fosfoproteínas/química , Estrutura Terciária de Proteína , Superóxidos/metabolismo , SuínosRESUMO
Junctional adhesion molecule A (JAM-A) is an immunoglobulin superfamily protein that plays an important role in the assembly and maintenance of tight junctions and the establishment of epithelial cell polarity. The feline JAM-A (fJAM-A) is a functional receptor for feline calicivirus (FCV). Among natural diseases associated with FCV infection, isolates that cause oral vesicular disease are detected in epithelial cells; however, isolates that cause systemic disease are detected in multiple cell types. The distribution of an FCV receptor or receptors in feline tissues is relevant to viral pathogenesis in that it should reflect the wide latitude of clinical sequelae associated with FCV infection. The authors examined the expression of feline JAM-A in the cat by using confocal immunofluorescence localization on normal tissues, with special regard to tissue targets of naturally occurring FCV. As described in the human and the mouse, fJAM-A was widely distributed in feline tissues, where it localized at cell-cell junctions of epithelial and endothelial cells. fJAM-A was highly expressed on feline platelets, with lower levels of expression on feline peripheral blood leukocytes. Additionally, FCV infection of a feline epithelial cell monolayer causes redistribution of fJAM-A to the cytosol of infected cells. It is reasonable to propose that the spectrum of lesions caused by FCV reflects disruption of intercellular junctions that rely on fJAM-A function and tight junctional integrity.
Assuntos
Calicivirus Felino/metabolismo , Moléculas de Adesão Celular/metabolismo , Células Epiteliais/metabolismo , Junções Intercelulares/metabolismo , Animais , Plaquetas/metabolismo , Gatos , Citometria de Fluxo , Imunofluorescência , Moléculas de Adesão Juncional , Microscopia ConfocalRESUMO
The ATP-binding cassette transporter (TAP) proteins are functionally relevant candidates for predisposition to systemic lupus erythematosus (SLE) by virtue of their role in autoantigen presentation and location in the major histocompatibility complex (MHC). We tested if variation in the TAP genes (TAP1 and TAP2) is associated with SLE. We genotyped tag single nucleotide polymorphisms (SNPs) and performed family-based association analysis on 390 Caucasian pedigrees. We found significant evidence of association between TAP2 and SLE (rs241453, P=1.33 x 10(-6)). Conditional logistic regression analysis suggests that this TAP2 effect is separate from the HLA-DRB1 alleles. Our analyses show that both rs241453 (P=1.6 x 10(-4)) and HLA-DRB1*03xx (P=2.3 x 10(-4)) have significant autonomous effects not due to linkage disequilibrium. Moreover, these loci exhibit a significant statistical interaction (P<1.0 x 10(-6)), demonstrated by an increase in the odds ratio for the TAP2 association from OR=2.00 (95% confidence interval (CI)=1.17-3.42) in HLA-DRB1*03xx-negative subjects to OR=4.29 (CI=1.88-9.76) in the subjects with at least one HLA-DRB1*03xx allele group. We report the largest association study of the TAP genes with SLE to date, and the first to test for its separate effect and interaction with the HLA alleles consistently associated with SLE.
Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Antígenos HLA-DR/genética , Desequilíbrio de Ligação/genética , Lúpus Eritematoso Sistêmico/genética , Membro 2 da Subfamília B de Transportadores de Cassetes de Ligação de ATP , Membro 3 da Subfamília B de Transportadores de Cassetes de Ligação de ATP , Adulto , Alelos , Feminino , Frequência do Gene/genética , Predisposição Genética para Doença , Genótipo , Cadeias HLA-DRB1 , Humanos , Modelos Logísticos , Lúpus Eritematoso Sistêmico/imunologia , Masculino , Polimorfismo de Nucleotídeo Único/genéticaRESUMO
Sjögren's syndrome (SS) is a common chronic autoimmune disease characterized by lymphocytic infiltration of exocrine glands. The affected cases commonly present with oral and ocular dryness, which is thought to be the result of inflammatory cell-mediated gland dysfunction. To identify important molecular pathways involved in SS, we used high-density microarrays to define global gene expression profiles in the peripheral blood. We first analyzed 21 SS cases and 23 controls, and identified a prominent pattern of overexpressed genes that are inducible by interferons (IFNs). These results were confirmed by evaluation of a second independent data set of 17 SS cases and 22 controls. Additional inflammatory and immune-related pathways with altered expression patterns in SS cases included B- and T-cell receptor, insulin-like growth factor-1, granulocyte macrophage-colony stimulating factor, peroxisome proliferator-activated receptor-alpha/retinoid X receptor-alpha and PI3/AKT signaling. Exploration of these data for relationships to clinical features of disease showed that expression levels for most interferon-inducible genes were positively correlated with titers of anti-Ro/SSA (P<0.001) and anti-La/SSB (P<0.001) autoantibodies. Diagnostic and therapeutic approaches targeting interferon-signaling pathway may prove most effective in the subset of SS cases that produce anti-Ro/SSA and anti-La/SSB autoantibodies. Our results strongly support innate and adaptive immune processes in the pathogenesis of SS, and provide numerous candidate disease markers for further study.
Assuntos
Autoimunidade/genética , Perfilação da Expressão Gênica , Imunidade Inata/genética , Síndrome de Sjogren/sangue , Síndrome de Sjogren/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Autoanticorpos/sangue , Estudos de Coortes , Feminino , Marcadores Genéticos , Humanos , Interferons/imunologia , Interferons/metabolismo , Masculino , Análise em Microsséries , Pessoa de Meia-Idade , Síndrome de Sjogren/imunologiaRESUMO
Systemic lupus erythematosus (SLE) is a complex autoimmune disease. Genome-wide linkage studies implicated a region containing the adhesion molecule P-Selectin. This family-based study revealed two regions of association within P-Selectin. The strongest signal, from a 21.4-kb risk haplotype, stretched from the promoter into the first two consensus repeat (CR) regions (P=8 x 10(-4)), with a second association from a 14.6-kb protective haplotype covering CR 2-9 (P=0.0198). The risk haplotype is tagged by the rare C allele of rs3753306, which disrupts the binding site of the trans-activating transcription factor HNF-1. One other variant (rs3917687) on the risk haplotype was significant after permutation (P(10000)<1 x 10(-5)), replicated in independent pseudo case-control analysis and was significant by meta-analysis (P=4.37 x 10(-6)). A third associated variant on the risk haplotype (rs3917657) replicated in 306 US SLE families and was significant in a joint UK-SLE data set after permutation. The protective haplotype is tagged by rs6133 (a non-synonymous variant in CR8 (P=9.00 x 10(-4)), which also shows association in the pseudo case-control analysis (P=1.09 x 10(-3)) and may contribute to another signal in P-Selectin. We propose that polymorphism in the upstream region may reduce expression of P-Selectin, the mechanism by which this promotes autoimmunity is unknown, although it may reduce the production of regulatory T cells.
Assuntos
Predisposição Genética para Doença , Lúpus Eritematoso Sistêmico/genética , Lúpus Eritematoso Sistêmico/imunologia , Selectina-P/genética , Regiões Promotoras Genéticas , Estudo de Associação Genômica Ampla , Humanos , Minnesota , Selectina-P/imunologia , Reino UnidoRESUMO
TNFAIP3 encodes the ubiquitin-modifying enzyme, A20, a key regulator of inflammatory signaling pathways. We previously reported association between TNFAIP3 variants and systemic lupus erythematosus (SLE). To further localize the risk variant(s), we performed a meta-analysis using genetic data available from two Caucasian case-control datasets (1453 total cases, 3381 total control subjects) and 713 SLE trio families. The best result was found at rs5029939 (P=1.67 x 10(-14), odds ratio=2.09, 95% confidence interval 1.68-2.60). We then imputed single nucleotide polymorphisms (SNPs) from the CEU Phase II HapMap using genotypes from 431 SLE cases and 2155 control subjects. Imputation identified 11 SNPs in addition to three observed SNPs, which together, defined a 109 kb SLE risk segment surrounding TNFAIP3. When evaluating whether the rs5029939 risk allele was associated with SLE clinical manifestations, we observed that heterozygous carriers of the TNFAIP3 risk allele at rs5029939 have a twofold increased risk of developing renal or hematologic manifestations compared to homozygous non-risk subjects. In summary, our study strengthens the genetic evidence that variants in the region of TNFAIP3 influence risk for SLE, particularly in patients with renal and hematologic manifestations, and narrows the risk effect to a 109 kb DNA segment that spans the TNFAIP3 gene.
Assuntos
Peptídeos e Proteínas de Sinalização Intracelular/genética , Nefrite Lúpica/genética , Proteínas Nucleares/genética , Proteínas de Ligação a DNA , Estudo de Associação Genômica Ampla , Haplótipos , Nefrite Lúpica/fisiopatologia , Polimorfismo de Nucleotídeo Único , Proteína 3 Induzida por Fator de Necrose Tumoral alfaRESUMO
Genetic factors influence susceptibility to systemic lupus erythematosus (SLE). A recent family-based analysis in Caucasian and Chinese populations provided evidence for association of single-nucleotide polymorphisms (SNPs) in the complement receptor 2 (CR2/CD21) gene with SLE. Here we confirmed this result in a case-control analysis of an independent European-derived population including 2084 patients with SLE and 2853 healthy controls. A haplotype formed by the minor alleles of three CR2 SNPs (rs1048971, rs17615, rs4308977) showed significant association with decreased risk of SLE (30.4% in cases vs 32.6% in controls, P=0.016, OR=0.90 (0.82-0.98)). Two of these SNPs are in exon 10, directly 5' of an alternatively spliced exon preferentially expressed in follicular dendritic cells (FDC), and the third is in the alternatively spliced exon. Effects of these SNPs and a fourth SNP in exon 11 (rs17616) on alternative splicing were evaluated. We found that the minor alleles of these SNPs decreased splicing efficiency of exon 11 both in vitro and ex vivo. These findings further implicate CR2 in the pathogenesis of SLE and suggest that CR2 variants alter the maintenance of tolerance and autoantibody production in the secondary lymphoid tissues where B cells and FDCs interact.