| 21. |
- Lundtoft, Christian, et al.
(författare)
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Complement C4 Copy Number Variation is Linked to SSA/Ro and SSB/La Autoantibodies in Systemic Inflammatory Autoimmune Diseases
- 2022
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Ingår i: Arthritis & Rheumatology. - : Wiley. - 2326-5191 .- 2326-5205. ; 74:8, s. 1440-1450
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Tidskriftsartikel (refereegranskat)abstract
- Objective Copy number variation of the C4 complement components, C4A and C4B, has been associated with systemic inflammatory autoimmune diseases. This study was undertaken to investigate whether C4 copy number variation is connected to the autoimmune repertoire in systemic lupus erythematosus (SLE), primary Sjogrens syndrome (SS), or myositis. Methods Using targeted DNA sequencing, we determined the copy number and genetic variants of C4 in 2,290 well-characterized Scandinavian patients with SLE, primary SS, or myositis and 1,251 healthy controls. Results A prominent relationship was observed between C4A copy number and the presence of SSA/SSB autoantibodies, which was shared between the 3 diseases. The strongest association was detected in patients with autoantibodies against both SSA and SSB and 0 C4A copies when compared to healthy controls (odds ratio [OR] 18.0 [95% confidence interval (95% CI) 10.2-33.3]), whereas a weaker association was seen in patients without SSA/SSB autoantibodies (OR 3.1 [95% CI 1.7-5.5]). The copy number of C4 correlated positively with C4 plasma levels. Further, a common loss-of-function variant in C4A leading to reduced plasma C4 was more prevalent in SLE patients with a low copy number of C4A. Functionally, we showed that absence of C4A reduced the individuals capacity to deposit C4b on immune complexes. Conclusion We show that a low C4A copy number is more strongly associated with the autoantibody repertoire than with the clinically defined disease entities. These findings may have implications for understanding the etiopathogenetic mechanisms of systemic inflammatory autoimmune diseases and for patient stratification when taking the genetic profile into account.
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| 22. |
- Löfgren, Sara E., et al.
(författare)
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A 3 '-Untranslated Region Variant Is Associated With Impaired Expression of CD226 in T and Natural Killer T Cells and Is Associated With Susceptibility to Systemic Lupus Erythematosus
- 2010
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Ingår i: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 62:11, s. 3404-3414
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Tidskriftsartikel (refereegranskat)abstract
- Objective. Costimulatory receptor CD226 plays an important role in T cell activation, differentiation, and cytotoxicity. This study was undertaken to investigate the genetic association of CD226 with susceptibility to systemic lupus erythematosus (SLE) and to assess the functional implications of this association. Methods. Twelve tag single-nucleotide polymorphisms (SNPs) in CD226 were typed in 1,163 SLE patients and 1,482 healthy control subjects from Europe or of European ancestry. Analyses of association were performed by single-marker Cochran-Mantel-Haenszel meta-analysis, followed by haplotype analysis. Gene expression was analyzed by quantitative real-time polymerase chain reaction analyses of RNA from peripheral blood mononuclear cells, and by fluorescence-activated cell sorter analysis. To study the functional impact of the associated variants, luciferase reporter constructs containing different portions of the 3'-untranslated region (3'-UTR) of the gene were prepared and used in transfection experiments. Results. A 3-variant haplotype, rs763361; rs34794968; rs727088 (ATC), in the last exon of CD226 was associated with SLE (P = 1.3 x 10(-4), odds ratio 1.24, 95% confidence interval 1.11-1.38). This risk haplotype correlated with low CD226 transcript expression and low CD226 protein levels on the surface of CD4+ and CD8+ T cells and natural killer T (NKT) cells. NK cells expressed high levels of CD226, but this expression was independent of the haplotype. Reporter assays with deletion constructs indicated that only the presence of rs727088 could account for the differences in the levels of luciferase transcripts. Conclusion. This study identified an association of CD226 with SLE in individuals of European ancestry. These data support the importance of the 3'-UTR SNP rs727088 in the regulation of CD226 transcription both in T cells and in NKT cells.
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| 23. |
- Löfgren, Sara E, et al.
(författare)
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Estrogen-dependent upregulation of IRF5 in human immune cells
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Objective: To contribute to the knowledge of the mechanisms behind the strong sex-biased prevalence of SLE, we investigated the role of estrogen on the expression of one of the strongest associated gene with SLE, the interferon regulatory factor 5 (IRF5), in human immune cells. Material and methods: IRF5, as well as IRF3, IRF4, IRF7 and IRF9 expression was measured in PBMCs, LCLs, monocytes and macrophages from both male and female origin. Cells were treated with different concentrations of estrogen and gene expression was measured by quantitative RT-PCR. Results: We found that the initial levels of IRF5 in PBMC were almost 2-fold higher in women than men, although not reaching statistical significance. After 12 h in culture the IRF5 levels became roughly equal in both sexes, and further stimulation with estrogen lead to up-regulation of IRF5 expression in both PBMCs and monocytes in both women and men. No difference was seen for IRF3, IRF4, IRF7 and IRF9 expression, and no gene was up-regulated in LCLs, upon estrogen treatment, regardless of the gender. Conclusions: We showed that in human PBMCs and monocytes from healthy individuals IRF5 expression can be regulated by exogenous estrogen. This feature might be specific to IRF5 since four other IRF genes tested did not show any up-regulation in these cells.
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| 24. |
- Löfgren, Sara E, et al.
(författare)
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Genetic association of miRNA-146a with systemic lupus erythematosus in Europeans through decreased expression of the gene
- 2012
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Ingår i: Genes and Immunity. - : Springer Science and Business Media LLC. - 1476-5470 .- 1466-4879. ; 13:3, s. 268-274
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Tidskriftsartikel (refereegranskat)abstract
- A recent genome-wide association study revealed a variant (rs2431697) in an intergenic region, between the pituitary tumor-transforming 1 (PTTG1) and microRNA (miR-146a) genes, associated with systemic lupus erythematosus (SLE) susceptibility. Here, we analyzed with a case-control design this variant and other candidate polymorphisms in this region together with expression analysis in order to clarify to which gene this association is related. The single-nucleotide polymorphisms (SNPs) rs2431697, rs2910164 and rs2277920 were genotyped by TaqMan assays in 1324 SLE patients and 1453 healthy controls of European ancestry. Genetic association was statistically analyzed using Unphased. Gene expression of PTTG1, the miRNAs miR-3142 and primary and mature forms of miR-146a in peripheral blood mononuclear cells (PBMCs) were assessed by quantitative real-time PCR. Of the three variants analyzed, only rs2431697 was genetically associated with SLE in Europeans. Gene expression analysis revealed that this SNP was not associated with PTTG1 expression levels, but with the microRNA-146a, where the risk allele correlates with lower expression of the miRNA. We replicated the genetic association of rs2341697 with SLE in a case-control study in Europeans and demonstrated that the risk allele of this SNP correlates with a downregulation of the miRNA 146a, potentially important in SLE etiology.
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| 25. |
- Löfgren, Sara E., et al.
(författare)
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Promoter Insertion/Deletion in the IRF5 Gene Is Highly Associated with Susceptibility to Systemic Lupus Erythematosus in Distinct Populations, But Exerts a Modest Effect on Gene Expression in Peripheral Blood Mononuclear Cells
- 2010
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Ingår i: Journal of Rheumatology. - : The Journal of Rheumatology. - 0315-162X .- 1499-2752. ; 37:3, s. 574-578
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Tidskriftsartikel (refereegranskat)abstract
- Objective. We examined the genetic association of the promoter insertion/deletion (indel) in IRF5 gene with systemic lupus erythematosus (SLE) in distinct populations and assessed its role in gene expression. Methods. Four IRF5 polymorphisms were genotyped in 1488 SLE patients and 1466 controls. Gene expression was analyzed by quantitative real-time PCR using RNA from peripheral blood mononuclear cells (PBMC). Results. The promoter indel and rs2070197 had independent genetic effects, which accounted for the association of rs2004640 and rs10954213. Gene expression analysis revealed that rs10954213 exerted the greatest influence on IRF5 transcript levels. Conclusion. We corroborated the association of the promoter indel with SLE in 5 different populations and revealed that rs10954213 is the main single-nucleotide polymorphism responsible for altered IRF5 expression in PBMC.
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| 26. |
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| 27. |
- Oparina, Nina Y., et al.
(författare)
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PXK locus in systemic lupus erythematosus : fine mapping and functional analysis reveals novel susceptibility gene ABHD6
- 2015
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 74:3
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Tidskriftsartikel (refereegranskat)abstract
- Objectives To perform fine mapping of the PXK locus associated with systemic lupus erythematosus (SLE) and study functional effects that lead to susceptibility to the disease. Methods Linkage disequilibrium (LD) mapping was conducted by using 1251 SNPs (single nucleotide polymorphism) covering a 862 kb genomic region on 3p14.3 comprising the PXK locus in 1467 SLE patients and 2377 controls of European origin. Tag SNPs and genotypes imputed with IMPUTE2 were tested for association by using SNPTEST and PLINK. The expression QTLs data included three independent datasets for lymphoblastoid cells of European donors: HapMap3, MuTHER and the cross-platform eQTL catalogue. Correlation analysis of eQTLs was performed using Vassarstats. Alternative splicing for the PXK gene was analysed on mRNA from PBMCs. Results Fine mapping revealed long-range LD (>200 kb) extended over the ABHD6, RPP14, PXK, and PDHB genes on 3p14.3. The highly correlated variants tagged an SLE-associated haplotype that was less frequent in the patients compared with the controls (OR=0.89, p=0.00684). A robust correlation between the association with SLE and enhanced expression of ABHD6 gene was revealed, while neither expression, nor splicing alterations associated with SLE susceptibility were detected for PXK. The SNP allele frequencies as well as eQTL pattern analysed in the CEU and CHB HapMap3 populations indicate that the SLE association and the effect on ABHD6 expression are specific to Europeans. Conclusions These results confirm the genetic association of the locus 3p14.3 with SLE in Europeans and point to the ABHD6 and not PXK, as the major susceptibility gene in the region. We suggest a pathogenic mechanism mediated by the upregulation of ABHD6 in individuals carrying the SLE-risk variants.
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| 28. |
- Roy, Ananya, et al.
(författare)
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Using evolutionary constraint to define novel candidate driver genes in medulloblastoma
- 2023
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences (PNAS). - 0027-8424 .- 1091-6490. ; 120:33
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Tidskriftsartikel (refereegranskat)abstract
- Current knowledge of cancer genomics remains biased against noncoding mutations. To systematically search for regulatory noncoding mutations, we assessed mutations in conserved positions in the genome under the assumption that these are more likely to be functional than mutations in positions with low conservation. To this end, we use whole-genome sequencing data from the International Cancer Genome Consortium and combined it with evolutionary constraint inferred from 240 mammals, to identify genes enriched in noncoding constraint mutations (NCCMs), mutations likely to be regulatory in nature. We compare medulloblastoma (MB), which is malignant, to pilocytic astrocytoma (PA), a primarily benign tumor, and find highly different NCCM frequencies between the two, in agreement with the fact that malignant cancers tend to have more mutations. In PA, a high NCCM frequency only affects the BRAF locus, which is the most commonly mutated gene in PA. In contrast, in MB, >500 genes have high levels of NCCMs. Intriguingly, several loci with NCCMs in MB are associated with different ages of onset, such as the HOXB cluster in young MB patients. In adult patients, NCCMs occurred in, e.g., the WASF-2/ AHDC1/FGR locus. One of these NCCMs led to increased expression of the SRC kinase FGR and augmented responsiveness of MB cells to dasatinib, a SRC kinase inhibitor. Our analysis thus points to different molecular pathways in different patient groups. These newly identified putative candidate driver mutations may aid in patient stratification in MB and could be valuable for future selection of personalized treatment options.
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| 29. |
- Sandling, Johanna K., et al.
(författare)
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Molecular pathways in patients with systemic lupus erythematosus revealed by gene-centred DNA sequencing
- 2021
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 80:1, s. 109-117
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Systemic lupus erythematosus (SLE) is an autoimmune disease with extensive heterogeneity in disease presentation between patients, which is likely due to an underlying molecular diversity. Here, we aimed at elucidating the genetic aetiology of SLE from the immunity pathway level to the single variant level, and stratify patients with SLE into distinguishable molecular subgroups, which could inform treatment choices in SLE. Methods: We undertook a pathway-centred approach, using sequencing of immunological pathway genes. Altogether 1832 candidate genes were analysed in 958 Swedish patients with SLE and 1026 healthy individuals. Aggregate and single variant association testing was performed, and we generated pathway polygenic risk scores (PRS). Results: We identified two main independent pathways involved in SLE susceptibility: T lymphocyte differentiation and innate immunity, characterised by HLA and interferon, respectively. Pathway PRS defined pathways in individual patients, who on average were positive for seven pathways. We found that SLE organ damage was more pronounced in patients positive for the T or B cell receptor signalling pathways. Further, pathway PRS-based clustering allowed stratification of patients into four groups with different risk score profiles. Studying sets of genes with priors for involvement in SLE, we observed an aggregate common variant contribution to SLE at genes previously reported for monogenic SLE as well as at interferonopathy genes. Conclusions: Our results show that pathway risk scores have the potential to stratify patients with SLE beyond clinical manifestations into molecular subsets, which may have implications for clinical follow-up and therapy selection.
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| 30. |
- Wilbe, Maria, et al.
(författare)
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Multiple Changes of Gene Expression and Function Reveal Genomic and Phenotypic Complexity in SLE-like Disease
- 2015
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Ingår i: PLOS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 11:6
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Tidskriftsartikel (refereegranskat)abstract
- The complexity of clinical manifestations commonly observed in autoimmune disorders poses a major challenge to genetic studies of such diseases. Systemic lupus erythematosus (SLE) affects humans as well as other mammals, and is characterized by the presence of antinuclear antibodies (ANA) in patients' sera and multiple disparate clinical features. Here we present evidence that particular sub-phenotypes of canine SLE-related disease, based on homogenous (ANA(H)) and speckled ANA (ANA(S)) staining pattern, and also steroid-responsive meningitis-arteritis (SRMA) are associated with different but overlapping sets of genes. In addition to association to certain MHC alleles and haplotypes, we identified 11 genes (WFDC3, HOMER2, VRK1, PTPN3, WHAMM, BANK1, AP3B2, DAPP1, LAM-TOR3, DDIT4L and PPP3CA) located on five chromosomes that contain multiple risk haplotypes correlated with gene expression and disease sub-phenotypes in an intricate manner. Intriguingly, the association of BANK1 with both human and canine SLE appears to lead to similar changes in gene expression levels in both species. Our results suggest that molecular definition may help unravel the mechanisms of different clinical features common between and specific to various autoimmune disease phenotypes in dogs and humans.
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