Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 246
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
2.
Artigo em Inglês | MEDLINE | ID: mdl-31600025

RESUMO

OBJECTIVE: The aim of this study was to determine the association of perceived stress with incident inflammatory arthritis (IA) defined as having at least 1 joint consistent with rheumatoid arthritis (RA)-like synovitis based on exam. METHODS: We conducted a prospective cohort study in the Studies of the Etiologies of Rheumatoid Arthritis (SERA). Participants without IA were recruited if they were a first degree relative of a RA proband or screened positive for anti-cyclic citrullinated peptide autoantibody (ACPA). Perceived stress was measured using the Perceived Stress Scale-14 (PSS) in which scores can range from 0 to 56 and a higher score indicates greater perceived stress. The total PSS score as well as two sub-scores indicative of perceived distress and self-efficacy were averaged across all study visits until development of IA or last follow-up. Hazard ratios (HRs) and 95% confidence intervals (CIs) of IA associated with average PSS scores were obtained using Cox proportional hazards models. RESULTS: The mean total PSS score was 20.4. We found that a one-point increase in the perceived distress score was significantly associated with a 10 percent increase in the risk of IA (adjusted HR: 1.10; 95%CI: 1.02, 1.19). Total PSS and self-efficacy were not associated with IA risk (adjusted HR: 1.05 (95%CI: 0.99, 1.10) and 1.04 (95%CI: 0.91, 1.18), respectively. CONCLUSIONS: An association between perceived distress and incident IA was observed in this at-risk cohort. Replication of this finding in other preclinical and at-risk RA populations is needed.

3.
Am J Hum Genet ; 105(3): 616-624, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31474319

RESUMO

Rheumatoid arthritis (RA) is the most common immune-mediated arthritis. Anti-citrullinated peptide antibodies (ACPA) are highly specific to RA and assayed with the commercial CCP2 assay. Genetic drivers of RA within the MHC are different for CCP2-positive and -negative subsets of RA, particularly at HLA-DRB1. However, aspartic acid at amino acid position 9 in HLA-B (Bpos-9) increases risk to both RA subsets. Here we explore how individual serologies associated with RA drive associations within the MHC. To define MHC differences for specific ACPA serologies, we quantified a total of 19 separate ACPAs in RA-affected case subjects from four cohorts (n = 6,805). We found a cluster of tightly co-occurring antibodies (canonical serologies, containing CCP2), along with several independently expressed antibodies (non-canonical serologies). After imputing HLA variants into 6,805 case subjects and 13,467 control subjects, we tested associations between the HLA region and RA subgroups based on the presence of canonical and/or non-canonical serologies. We examined CCP2(+) and CCP2(-) RA-affected case subjects separately. In CCP2(-) RA, we observed that the association between CCP2(-) RA and Bpos-9 was derived from individuals who were positive for non-canonical serologies (omnibus_p = 9.2 × 10-17). Similarly, we observed in CCP2(+) RA that associations between subsets of CCP2(+) RA and Bpos-9 were negatively correlated with the number of positive canonical serologies (p = 0.0096). These findings suggest unique genetic characteristics underlying fine-specific ACPAs, suggesting that RA may be further subdivided beyond simply seropositive and seronegative.

4.
Ann Rheum Dis ; 78(7): 996-1002, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31138531

RESUMO

OBJECTIVES: Idiopathic inflammatory myopathies (IIM) are a spectrum of rare autoimmune diseases characterised clinically by muscle weakness and heterogeneous systemic organ involvement. The strongest genetic risk is within the major histocompatibility complex (MHC). Since autoantibody presence defines specific clinical subgroups of IIM, we aimed to correlate serotype and genotype, to identify novel risk variants in the MHC region that co-occur with IIM autoantibodies. METHODS: We collected available autoantibody data in our cohort of 2582 Caucasian patients with IIM. High resolution human leucocyte antigen (HLA) alleles and corresponding amino acid sequences were imputed using SNP2HLA from existing genotyping data and tested for association with 12 autoantibody subgroups. RESULTS: We report associations with eight autoantibodies reaching our study-wide significance level of p<2.9×10-5. Associations with the 8.1 ancestral haplotype were found with anti-Jo-1 (HLA-B*08:01, p=2.28×10-53 and HLA-DRB1*03:01, p=3.25×10-9), anti-PM/Scl (HLA-DQB1*02:01, p=1.47×10-26) and anti-cN1A autoantibodies (HLA-DRB1*03:01, p=1.40×10-11). Associations independent of this haplotype were found with anti-Mi-2 (HLA-DRB1*07:01, p=4.92×10-13) and anti-HMGCR autoantibodies (HLA-DRB1*11, p=5.09×10-6). Amino acid positions may be more strongly associated than classical HLA associations; for example with anti-Jo-1 autoantibodies and position 74 of HLA-DRB1 (p=3.47×10-64) and position 9 of HLA-B (p=7.03×10-11). We report novel genetic associations with HLA-DQB1 anti-TIF1 autoantibodies and identify haplotypes that may differ between adult-onset and juvenile-onset patients with these autoantibodies. CONCLUSIONS: These findings provide new insights regarding the functional consequences of genetic polymorphisms within the MHC. As autoantibodies in IIM correlate with specific clinical features of disease, understanding genetic risk underlying development of autoantibody profiles has implications for future research.

5.
Nat Immunol ; 20(7): 928-942, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31061532

RESUMO

To define the cell populations that drive joint inflammation in rheumatoid arthritis (RA), we applied single-cell RNA sequencing (scRNA-seq), mass cytometry, bulk RNA sequencing (RNA-seq) and flow cytometry to T cells, B cells, monocytes, and fibroblasts from 51 samples of synovial tissue from patients with RA or osteoarthritis (OA). Utilizing an integrated strategy based on canonical correlation analysis of 5,265 scRNA-seq profiles, we identified 18 unique cell populations. Combining mass cytometry and transcriptomics revealed cell states expanded in RA synovia: THY1(CD90)+HLA-DRAhi sublining fibroblasts, IL1B+ pro-inflammatory monocytes, ITGAX+TBX21+ autoimmune-associated B cells and PDCD1+ peripheral helper T (TPH) cells and follicular helper T (TFH) cells. We defined distinct subsets of CD8+ T cells characterized by GZMK+, GZMB+, and GNLY+ phenotypes. We mapped inflammatory mediators to their source cell populations; for example, we attributed IL6 expression to THY1+HLA-DRAhi fibroblasts and IL1B production to pro-inflammatory monocytes. These populations are potentially key mediators of RA pathogenesis.


Assuntos
Artrite Reumatoide/genética , Artrite Reumatoide/metabolismo , Perfilação da Expressão Gênica , Membrana Sinovial/metabolismo , Transcriptoma , Artrite Reumatoide/patologia , Autoimunidade/genética , Biomarcadores , Biologia Computacional/métodos , Estudos Transversais , Citocinas/metabolismo , Fibroblastos/metabolismo , Citometria de Fluxo , Expressão Gênica , Perfilação da Expressão Gênica/métodos , Sequenciamento de Nucleotídeos em Larga Escala , Antígenos de Histocompatibilidade Classe II/genética , Antígenos de Histocompatibilidade Classe II/imunologia , Humanos , Leucócitos/imunologia , Leucócitos/metabolismo , Monócitos/imunologia , Monócitos/metabolismo , Transdução de Sinais , Análise de Célula Única/métodos , Membrana Sinovial/patologia , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Fluxo de Trabalho
6.
J Rheumatol ; 46(12): 1556-1559, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30988128

RESUMO

OBJECTIVE: We investigated the association of age and anticyclic citrullinated peptide antibodies (anti-CCP) in subjects without rheumatoid arthritis (RA). METHODS: Serum was tested for anti-CCP3.1 (IgG/IgA) in 678 first-degree relatives (FDR) of patients with RA and 330 patients with osteoarthritis (OA). Individual isotypes (anti-CCP-IgA and anti-CCP-IgG) were also tested in all FDR. RESULTS: In FDR, increasing age was significantly associated with positivity for anti-CCP3.1 (per year, OR 1.03) and anti-CCP-IgA (per year, OR 1.05) but not anti-CCP-IgG. In FDR and OA subjects, anti-CCP3.1 prevalence was significantly increased after age 50 years. CONCLUSION: Increasing age in individuals without RA should be considered in the interpretation of anti-CCP3.1 positivity.

7.
Diabetes Care ; 42(3): 406-415, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30659077

RESUMO

OBJECTIVE: Genetic risk scores (GRS) have been developed that differentiate individuals with type 1 diabetes from those with other forms of diabetes and are starting to be used for population screening; however, most studies were conducted in European-ancestry populations. This study identifies novel genetic variants associated with type 1 diabetes risk in African-ancestry participants and develops an African-specific GRS. RESEARCH DESIGN AND METHODS: We generated single nucleotide polymorphism (SNP) data with the ImmunoChip on 1,021 African-ancestry participants with type 1 diabetes and 2,928 control participants. HLA class I and class II alleles were imputed using SNP2HLA. Logistic regression models were used to identify genome-wide significant (P < 5.0 × 10-8) SNPs associated with type 1 diabetes in the African-ancestry samples and validate SNPs associated with risk in known European-ancestry loci (P < 2.79 × 10-5). RESULTS: African-specific (HLA-DQA1*03:01-HLA-DQB1*02:01) and known European-ancestry HLA haplotypes (HLA-DRB1*03:01-HLA-DQA1*05:01-HLA-DQB1*02:01, HLA-DRB1*04:01-HLA-DQA1*03:01-HLA-DQB1*03:02) were significantly associated with type 1 diabetes risk. Among European-ancestry defined non-HLA risk loci, six risk loci were significantly associated with type 1 diabetes in subjects of African ancestry. An African-specific GRS provided strong prediction of type 1 diabetes risk (area under the curve 0.871), performing significantly better than a European-based GRS and two polygenic risk scores in independent discovery and validation cohorts. CONCLUSIONS: Genetic risk of type 1 diabetes includes ancestry-specific, disease-associated variants. The GRS developed here provides improved prediction of type 1 diabetes in African-ancestry subjects and a means to identify groups of individuals who would benefit from immune monitoring for early detection of islet autoimmunity.


Assuntos
Grupo com Ancestrais do Continente Africano/genética , Diabetes Mellitus Tipo 1/etnologia , Diabetes Mellitus Tipo 1/genética , Testes Genéticos , Antígenos HLA-D/genética , Grupo com Ancestrais do Continente Africano/estatística & dados numéricos , Alelos , Estudos de Casos e Controles , Grupo com Ancestrais do Continente Europeu/genética , Feminino , Predisposição Genética para Doença , Testes Genéticos/métodos , Testes Genéticos/normas , Estudo de Associação Genômica Ampla , Cadeias alfa de HLA-DQ/genética , Cadeias beta de HLA-DQ/genética , Cadeias HLA-DRB1/genética , Haplótipos , Humanos , Masculino , Polimorfismo de Nucleotídeo Único , Valor Preditivo dos Testes , Projetos de Pesquisa , Fatores de Risco
8.
Ann Rheum Dis ; 78(3): 311-319, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30573655

RESUMO

OBJECTIVE: Immune-mediated inflammatory diseases (IMIDs) are heterogeneous and complex conditions with overlapping clinical symptoms and elevated familial aggregation, which suggests the existence of a shared genetic component. In order to identify this genetic background in a systematic fashion, we performed the first cross-disease genome-wide meta-analysis in systemic seropositive rheumatic diseases, namely, systemic sclerosis, systemic lupus erythematosus, rheumatoid arthritis and idiopathic inflammatory myopathies. METHODS: We meta-analysed ~6.5 million single nucleotide polymorphisms in 11 678 cases and 19 704 non-affected controls of European descent populations. The functional roles of the associated variants were interrogated using publicly available databases. RESULTS: Our analysis revealed five shared genome-wide significant independent loci that had not been previously associated with these diseases: NAB1, KPNA4-ARL14, DGQK, LIMK1 and PRR12. All of these loci are related with immune processes such as interferon and epidermal growth factor signalling, response to methotrexate, cytoskeleton dynamics and coagulation cascade. Remarkably, several of the associated loci are known key players in autoimmunity, which supports the validity of our results. All the associated variants showed significant functional enrichment in DNase hypersensitivity sites, chromatin states and histone marks in relevant immune cells, including shared expression quantitative trait loci. Additionally, our results were significantly enriched in drugs that are being tested for the treatment of the diseases under study. CONCLUSIONS: We have identified shared new risk loci with functional value across diseases and pinpoint new potential candidate loci that could be further investigated. Our results highlight the potential of drug repositioning among related systemic seropositive rheumatic IMIDs.


Assuntos
Artrite Reumatoide/genética , Lúpus Eritematoso Sistêmico/genética , Miosite/genética , Locos de Características Quantitativas/genética , Doenças Reumáticas/genética , Escleroderma Sistêmico/genética , Adulto , Artrite Reumatoide/imunologia , Grupo com Ancestrais do Continente Europeu/genética , Feminino , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Quinases Lim/imunologia , Lúpus Eritematoso Sistêmico/imunologia , Masculino , Proteínas de Membrana/imunologia , Miosite/imunologia , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas/imunologia , Proteínas Repressoras/imunologia , Doenças Reumáticas/imunologia , Escleroderma Sistêmico/imunologia , alfa Carioferinas/imunologia
10.
PLoS One ; 13(11): e0206785, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30383866

RESUMO

Here we investigated different cell populations within ovarian cancer using single-cell RNA seq: fourteen samples from nine patients with differing grades (high grade, low grade and benign) as well as different origin sites (primary and metastatic tumor site, ovarian in origin and fallopian in origin). We were able to identify sixteen distinct cell populations with specific cells correlated to high grade tumors, low grade tumors, benign and one population unique to a patient with a breast cancer relapse. Furthermore the proportion of these populations changes from primary to metastatic in a shift from mainly epithelial cells to leukocytes with few cancer epithelial cells in the metastases. Differential gene expression shows myeloid lineage cells are the primary cell group expressing soluble factors in primary samples while fibroblasts do so in metastatic samples. The leukocytes that were captured did not seem to be suppressed through known pro-tumor cytokines from any of the cell populations. Single cell RNA-seq is necessary to de-tangle cellular heterogeneity for better understanding of ovarian cancer progression.

11.
Hum Mol Genet ; 2018 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-30423114

RESUMO

Large meta-analyses of RA susceptibility in European and East Asian populations have identified >100 RA risk loci, but genome-wide studies of RA in African-Americans are absent. To address this disparity, we performed an analysis of 916 African-American RA patients and 1392 controls, and aggregated our data with genotyping data from >100,000 European and Asian RA patients and controls. We identified two novel risk loci that appear to be specific to African-Americans: GPC5 and RBFOX1 (pAA < 5 x 10-9). Most RA risk loci are shared across different ethnicities, but among discordant loci, we observed strong enrichment of variants having large effect sizes. We found strong evidence of effect concordance for only 3 of the 21 largest effect index variants in Europeans. We used the trans-ethnic fine-mapping algorithm PAINTOR3 to prioritize risk variants in >90 RA risk loci. Addition of African-American data to those of European and East Asian descent enabled identification of 7 novel high confidence candidate pathogenic variants (defined by posterior probability > 0.8). In summary, our trans-ethnic analyses are the first to include African-Americans, identified several new RA risk loci, and point to candidate pathogenic variants that may underlie this common autoimmune disease. These findings may lead to better ways to diagnose or stratify treatment approaches in RA.

13.
Nat Genet ; 50(10): 1366-1374, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30224649

RESUMO

To define potentially causal variants for autoimmune disease, we fine-mapped1,2 76 rheumatoid arthritis (11,475 cases, 15,870 controls)3 and type 1 diabetes loci (9,334 cases, 11,111 controls)4. After sequencing 799 1-kilobase regulatory (H3K4me3) regions within these loci in 568 individuals, we observed accurate imputation for 89% of common variants. We defined credible sets of ≤5 causal variants at 5 rheumatoid arthritis and 10 type 1 diabetes loci. We identified potentially causal missense variants at DNASE1L3, PTPN22, SH2B3, and TYK2, and noncoding variants at MEG3, CD28-CTLA4, and IL2RA. We also identified potential candidate causal variants at SIRPG and TNFAIP3. Using functional assays, we confirmed allele-specific protein binding and differential enhancer activity for three variants: the CD28-CTLA4 rs117701653 SNP, MEG3 rs34552516 indel, and TNFAIP3 rs35926684 indel.

14.
Mol Med ; 24(1): 1, 2018 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-30134794

RESUMO

BACKGROUND: Endometriosis is a chronic and underdiagnosed disease which affects 5-10% of women of childbearing age and is characterized by growth of endometrial tissue outside of the uterus, most often in the peritoneal cavity. Delay in diagnosis is a major problem for management of this disorder, and treatment is often not initiated until the disease has progressed for many years. Although the exact etiology of endometriosis remains unknown, retrograde menstruation is recognized as a common underlying factor leading to the deposit of menstrual effluent (ME) into the peritoneal cavity. Differences in the cellular biology and genetics of the cells within ME are therefore likely to explain why endometriosis develops in only a subset of women. METHODS: Patients with and without endometriosis were consented to provide ME. ME was analyzed by flow cytometry for CD45- and CD45+ cell populations or used to isolate stromal fibroblast cells. ME-derived stromal fibroblast cells were assessed using decidualization assays following the addition of cAMP and IGFBP-1 concentrations in the culture supernatants were measured by ELISA. In addition, RNA was collected and analyzed by RNA-Seq and qPCR for markers of decidualization and to identify differentially expressed genes in ME-derived stromal fibroblast cells obtained from controls and subjects with endometriosis (±cAMP). RESULTS: Flow cytometry analysis of cell subsets within the CD45+ fraction of ME revealed a significant decrease in the number of uterine NK cells in endometriosis patients compared with controls (p < 0.01). No other significant differences within either the CD45+ or CD45- cell populations were observed. Most strikingly, ME-derived stromal fibroblast cells cultured from endometriosis subjects showed impaired decidualization potential compared with controls. Highly significant differences in decidualization response were detected by measuring IGFBP-1 production at multiple time points after cAMP stimulation (p = 0.0025 at 6 h; p = 0.0045 at 24 h; p = 0.0125 at 48 h). RNA-Seq and qPCR analyses were used to identify genes differentially expressed by ME-derived stromal fibroblast cells obtained from endometriosis and control subjects. CONCLUSIONS: Menstrual effluent can be useful for investigating the pathobiology of endometriosis and for developing a non-invasive diagnostic for endometriosis which may lead to earlier and more effective treatments for this common disorder.

15.
Mol Med ; 24(1): 24, 2018 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-30134810

RESUMO

BACKGROUND: Systemic lupus erythematosus (SLE) is an autoimmune disease with genetic, hormonal, and environmental influences. In Western Europe and North America, individuals of West African descent have a 3-4 fold greater incidence of SLE than Caucasians. Paradoxically, West Africans in sub-Saharan Africa appear to have a low incidence of SLE, and some studies suggest a milder disease with less nephritis. In this study, we analyzed sera from African American female SLE patients and four other cohorts, one with SLE and others with varying degrees of risk for SLE in order to identify serologic factors that might correlate with risk of or protection against SLE. METHODS: Our cohorts included West African women with previous malaria infection assumed to be protected from development of SLE, clinically unaffected sisters of SLE patients with high risk of developing SLE, healthy African American women with intermediate risk, healthy Caucasian women with low risk of developing SLE, and women with a diagnosis of SLE. We developed a lupus risk index (LRI) based on titers of IgM and IgG anti-double stranded DNA antibodies and levels of C1q. RESULTS: The risk index was highest in SLE patients; second highest in unaffected sisters of SLE patients; third highest in healthy African-American women and lowest in healthy Caucasian women and malaria-exposed West African women. CONCLUSION: This risk index may be useful in early interventions to prevent SLE. In addition, it suggests new therapeutic approaches for the treatment of SLE.

16.
Arthritis Res Ther ; 20(1): 139, 2018 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-29996944

RESUMO

BACKGROUND: Detailed molecular analyses of cells from rheumatoid arthritis (RA) synovium hold promise in identifying cellular phenotypes that drive tissue pathology and joint damage. The Accelerating Medicines Partnership RA/SLE Network aims to deconstruct autoimmune pathology by examining cells within target tissues through multiple high-dimensional assays. Robust standardized protocols need to be developed before cellular phenotypes at a single cell level can be effectively compared across patient samples. METHODS: Multiple clinical sites collected cryopreserved synovial tissue fragments from arthroplasty and synovial biopsy in a 10% DMSO solution. Mechanical and enzymatic dissociation parameters were optimized for viable cell extraction and surface protein preservation for cell sorting and mass cytometry, as well as for reproducibility in RNA sequencing (RNA-seq). Cryopreserved synovial samples were collectively analyzed at a central processing site by a custom-designed and validated 35-marker mass cytometry panel. In parallel, each sample was flow sorted into fibroblast, T-cell, B-cell, and macrophage suspensions for bulk population RNA-seq and plate-based single-cell CEL-Seq2 RNA-seq. RESULTS: Upon dissociation, cryopreserved synovial tissue fragments yielded a high frequency of viable cells, comparable to samples undergoing immediate processing. Optimization of synovial tissue dissociation across six clinical collection sites with ~ 30 arthroplasty and ~ 20 biopsy samples yielded a consensus digestion protocol using 100 µg/ml of Liberase™ TL enzyme preparation. This protocol yielded immune and stromal cell lineages with preserved surface markers and minimized variability across replicate RNA-seq transcriptomes. Mass cytometry analysis of cells from cryopreserved synovium distinguished diverse fibroblast phenotypes, distinct populations of memory B cells and antibody-secreting cells, and multiple CD4+ and CD8+ T-cell activation states. Bulk RNA-seq of sorted cell populations demonstrated robust separation of synovial lymphocytes, fibroblasts, and macrophages. Single-cell RNA-seq produced transcriptomes of over 1000 genes/cell, including transcripts encoding characteristic lineage markers identified. CONCLUSIONS: We have established a robust protocol to acquire viable cells from cryopreserved synovial tissue with intact transcriptomes and cell surface phenotypes. A centralized pipeline to generate multiple high-dimensional analyses of synovial tissue samples collected across a collaborative network was developed. Integrated analysis of such datasets from large patient cohorts may help define molecular heterogeneity within RA pathology and identify new therapeutic targets and biomarkers.

17.
Front Immunol ; 9: 996, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29867973

RESUMO

Interferon regulatory factor 5 (IRF5) is widely recognized as a risk locus for systemic lupus erythematosus (SLE). Risk gene and IRF5 activation is triggered through toll-like receptor signaling. In myeloid cells, this leads to production of type I interferon and inflammatory cytokines, with enhanced production in cells of individuals harboring IRF5 risk alleles. Mouse models have also demonstrated the importance of IRF5 in B cell function, particularly plasma cell differentiation and isotype switching. Here, we evaluated the major SLE risk haplotype of IRF5 on the functional attributes of freshly isolated B cells from human subjects who do not have evidence of SLE or other forms of autoimmunity. We took this approach to avoid the complications of studying genotype-phenotype relationships in B cells that have been chronically exposed to an inflammatory disease environment before isolation. We focused on B cell endophenotypes that included gene expression, antibody secretion, class switching, and apoptotic susceptibility. We performed IRF5 overexpression studies, genetic reporter assays and electro-mobility shift assays on B and myeloid cell lines. Somewhat surprisingly, the results of our analyses indicate that IRF5 risk genotypes do not have a B cell intrinsic effect on these B cell functions. By contrast, we confirmed that the IRF5 risk and non-risk haplotypes exert differential effects in myeloid cells, including an increased susceptibility to apoptosis conferred by the risk haplotype. We also demonstrated an increased binding of the transcription factor specificity protein 1 to an insertion/deletion present in the risk haplotype. Our findings raise the specter that genetic risk alleles can have complex and unexpected lineage-specific effects, and these must be carefully considered when guiding or developing therapies based on understanding disease risk haplotypes.

18.
PLoS One ; 13(1): e0189498, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29293537

RESUMO

Gene-level analysis of ImmunoChip or genome-wide association studies (GWAS) data has not been previously reported for systemic sclerosis (SSc, scleroderma). The objective of this study was to analyze genetic susceptibility loci in SSc at the gene level and to determine if the detected associations were shared in African-American and White populations, using data from ImmunoChip and GWAS genotyping studies. The White sample included 1833 cases and 3466 controls (956 cases and 2741 controls from the US and 877 cases and 725 controls from Spain) and the African American sample, 291 cases and 260 controls. In both Whites and African Americans, we performed a gene-level analysis that integrates association statistics in a gene possibly harboring multiple SNPs with weak effect on disease risk, using Versatile Gene-based Association Study (VEGAS) software. The SNP-level analysis was performed using PLINK v.1.07. We identified 4 novel candidate genes (STAT1, FCGR2C, NIPSNAP3B, and SCT) significantly associated and 4 genes (SERBP1, PINX1, TMEM175 and EXOC2) suggestively associated with SSc in the gene level analysis in White patients. As an exploratory analysis we compared the results on Whites with those from African Americans. Of previously established susceptibility genes identified in Whites, only TNFAIP3 was significant at the nominal level (p = 6.13x10-3) in African Americans in the gene-level analysis of the ImmunoChip data. Among the top suggestive novel genes identified in Whites based on the ImmunoChip data, FCGR2C and PINX1 were only nominally significant in African Americans (p = 0.016 and p = 0.028, respectively), while among the top novel genes identified in the gene-level analysis in African Americans, UNC5C (p = 5.57x10-4) and CLEC16A (p = 0.0463) were also nominally significant in Whites. We also present the gene-level analysis of SSc clinical and autoantibody phenotypes among Whites. Our findings need to be validated by independent studies, particularly due to the limited sample size of African Americans.


Assuntos
Grupo com Ancestrais do Continente Africano/genética , Grupo com Ancestrais do Continente Europeu/genética , Estudo de Associação Genômica Ampla , Escleroderma Sistêmico/genética , Humanos , Polimorfismo de Nucleotídeo Único
19.
Nat Immunol ; 18(9): 1016-1024, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28692065

RESUMO

Aberrant population expansion of follicular helper T cells (TFH cells) occurs in patients with lupus. An unanswered question is whether an altered repertoire of T cell antigen receptors (TCRs) is associated with such expansion. Here we found that the transcription factor Blimp-1 (encoded by Prdm1) repressed expression of the gene encoding cathepsin S (Ctss), a cysteine protease that cleaves invariant chains and produces antigenic peptides for loading onto major histocompatibility complex (MHC) class II molecules. The increased CTSS expression in dendritic cells (DCs) from female mice with dendritic cell-specific conditional knockout of Prdm1 (CKO mice) altered the presentation of antigen to CD4+ T cells. Analysis of complementarity-determining region 3 (CDR3) regions containing the ß-chain variable region (Vß) demonstrated a more diverse repertoire of TFH cells from female CKO mice than of those from wild-type mice. In vivo treatment of CKO mice with a CTSS inhibitor abolished the lupus-related phenotype and reduced the diversity of the TFH cell TCR repertoire. Thus, Blimp-1 deficiency in DCs led to loss of appropriate regulation of Ctss expression in female mice and thereby modulated antigen presentation and the TFH cell repertoire to contribute to autoimmunity.


Assuntos
Catepsinas/metabolismo , Células Dendríticas/metabolismo , Lúpus Eritematoso Sistêmico/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Fatores de Transcrição/genética , Animais , Anticorpos Antinucleares/imunologia , Apresentação do Antígeno/imunologia , Linfócitos T CD4-Positivos/imunologia , Diferenciação Celular , Proliferação de Células , DNA/imunologia , Células Dendríticas/imunologia , Ensaio de Imunoadsorção Enzimática , Feminino , Rim/patologia , Lúpus Eritematoso Sistêmico/patologia , Ativação Linfocitária , Camundongos , Camundongos Knockout , Fator 1 de Ligação ao Domínio I Regulador Positivo , Receptores de Antígenos de Linfócitos T alfa-beta/genética
20.
Mol Med ; 23: 177-187, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28681901

RESUMO

Over 100 risk loci for rheumatoid arthritis (RA) have been identified in individuals of European and Asian descent, but the genetic basis for RA in African Americans is less well understood. We genotyped 610 African Americans with autoantibody positive RA and 933 African American controls on the ImmunoChip (iChip) array. Using multivariable regression we evaluated the association between iChip markers and the risk of RA and radiographic severity. The single nucleotide polymorphism (SNP) rs1964995 (OR = 1.97, p = 1.28 × 10-15) near HLA-DRB1 was the most strongly associated risk SNP for RA susceptibility; SNPs in AFF3, TNFSF11, and TNFSF18 loci were suggestively associated (10-4 < p < 3.1 × 10-6). Trans-ethnic fine mapping of AFF3 identified a 90% credible set containing previously studied variants including rs9653442, rs7608424, and rs6712515 as well as the novel candidate variant rs11681966; several of these likely influence AFF3 gene expression level. Variants in TNFRSF9, CTLA4, IL2RA, C5/TRAF1, and ETS1 - but no variants within the major histocompatibility complex - were associated with RA radiographic severity. Conditional regression and pairwise linkage disequilibrium (LD) analyses suggest that additional pathogenic variants may be found in ETS1 and IL2RA beyond those found in other ethnicities. In summary, we use the dense genotyping of the iChip array and unique LD structure of African Americans to validate known risk loci for RA susceptibility and radiographic severity, and to better characterize the associations of AFF3, ETS1, and IL2RA.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA