| 1. |
- Carlsson Almlöf, Jonas, et al.
(författare)
-
Novel risk genes for systemic lupus erythematosus predicted by random forest classification
- 2017
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7:1
-
Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies have identified risk loci for SLE, but a large proportion of the genetic contribution to SLE still remains unexplained. To detect novel risk genes, and to predict an individual's SLE risk we designed a random forest classifier using SNP genotype data generated on the "Immunochip" from 1,160 patients with SLE and 2,711 controls. Using gene importance scores defined by the random forest classifier, we identified 15 potential novel risk genes for SLE. Of them 12 are associated with other autoimmune diseases than SLE, whereas three genes (ZNF804A, CDK1, and MANF) have not previously been associated with autoimmunity. Random forest classification also allowed prediction of patients at risk for lupus nephritis with an area under the curve of 0.94. By allele-specific gene expression analysis we detected cis-regulatory SNPs that affect the expression levels of six of the top 40 genes designed by the random forest analysis, indicating a regulatory role for the identified risk variants. The 40 top genes from the prediction were overrepresented for differential expression in B and T cells according to RNA-sequencing of samples from five healthy donors, with more frequent over-expression in B cells compared to T cells.
|
|
| 2. |
|
|
| 3. |
- Chemin, Karine, et al.
(författare)
-
A Novel HLA-DRB1*10:01-Restricted T Cell Epitope From Citrullinated Type II Collagen Relevant to Rheumatoid Arthritis
- 2016
-
Ingår i: Arthritis & Rheumatology. - : Wiley. - 2326-5191 .- 2326-5205. ; 68:5, s. 1124-1135
-
Tidskriftsartikel (refereegranskat)abstract
- Objective. Antibodies against citrullinated type II collagen (Cit-CII) are common in the sera and synovial fluid of patients with rheumatoid arthritis (RA); however, the known T cell epitope of CII is not dependent on citrullination. The aim of this study was to identify and functionally characterize the Cit-CII-restricted T cell epitopes that are relevant to RA. Methods. Peripheral blood mononuclear cells (PBMCs) from HLA-DRB1*10:01-positive patients with RA and healthy donors were stimulated in vitro with candidate CII peptides. CD154 up-regulation was measured as a marker of antigen-specific activation, and anti-HLA-DR-blocking experiments confirmed HLA restriction. Cytokine production was measured using a Luminex technique. Direct peptide-binding assays using HLA-DRB1*10:01 and HLA-DRB1*04:01 monomeric proteins were performed. The T cell receptor (TCR) beta-chain of CD154-enriched antigen-specific T cells was analyzed using high-throughput sequencing. Results. A novel Cit-CII peptide was identified based on its ability to activate CD4+ T cells from HLA-DRB1*10:01-positive individuals. When stimulated in vitro, Cit-CII autoreactive T cells produced proinflammatory cytokines. Cit-CII311-325 bound (with low affinity) to HLA-DRB1*10:01 but not to HLA-DRB1*04:01, while the native form was unable to bind either protein. In addition, highly expanded clones were identified in the TCR beta repertoire of Cit-CII311-325-stimulated PBMCs. Conclusion. These results illustrate the ability of the citrullination process to create T cell epitopes from CII, a cartilage-restricted protein that is relevant to RA pathogenesis. The exclusive binding of Cit-CII311-325 to HLA-DRB1*10:01 suggests that recognition of citrullinated epitopes might vary between individuals carrying different RA-associated HLA-DR molecules.
|
|
| 4. |
- Chemin, Karine, et al.
(författare)
-
EOMES-positive CD4+ T cells are increased in PTPN22 (1858T) risk allele carriers.
- 2018
-
Ingår i: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 48:4, s. 655-669
-
Tidskriftsartikel (refereegranskat)abstract
- The presence of the PTPN22 risk allele (1858T) is associated with several autoimmune diseases including rheumatoid arthritis (RA). Despite a number of studies exploring the function of PTPN22 in T cells, the exact impact of the PTPN22 risk allele on T-cell function in humans is still unclear. In this study, using RNA sequencing, we show that, upon TCR-activation, naïve human CD4+ T cells homozygous for the PTPN22 risk allele overexpress a set of genes including CFLAR and 4-1BB, which are important for cytotoxic T-cell differentiation. Moreover, the protein expression of the T-box transcription factor Eomesodermin (EOMES) was increased in T cells from healthy donors homozygous for the PTPN22 risk allele and correlated with a decreased number of naïve CD4+ T cells. There was no difference in the frequency of other CD4+ T cell subsets (Th1, Th17, Tfh, Treg). Finally, an accumulation of EOMES+CD4+ T cells was observed in synovial fluid of RA patients with a more pronounced production of Perforin-1 in PTPN22 risk allele carriers. Altogether, we propose a novel mechanism of action of PTPN22 risk allele through the generation of cytotoxic CD4+ T cells and identify EOMES+CD4+ T cells as a relevant T-cell subset in RA pathogenesis.
|
|
| 5. |
- Eriksson, Daniel, et al.
(författare)
-
Common genetic variation in the autoimmune regulator (AIRE) locus is associated with autoimmune Addison’s disease in Sweden
- 2018
-
Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 8:1
-
Tidskriftsartikel (refereegranskat)abstract
- Autoimmune Addison's disease (AAD) is the predominating cause of primary adrenal failure. Despite its high heritability, the rarity of disease has long made candidate-gene studies the only feasible methodology for genetic studies. Here we conducted a comprehensive reinvestigation of suggested AAD risk loci and more than 1800 candidate genes with associated regulatory elements in 479 patients with AAD and 2394 controls. Our analysis enabled us to replicate many risk variants, but several other previously suggested risk variants failed confirmation. By exploring the full set of 1800 candidate genes, we further identified common variation in the autoimmune regulator (AIRE) as a novel risk locus associated to sporadic AAD in our study. Our findings not only confirm that multiple loci are associated with disease risk, but also show to what extent the multiple risk loci jointly associate to AAD. In total, risk loci discovered to date only explain about 7% of variance in liability to AAD in our study population.
|
|
| 6. |
- Eriksson, D, et al.
(författare)
-
Extended exome sequencing identifies BACH2 as a novel major risk locus for Addison's disease
- 2016
-
Ingår i: Journal of Internal Medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 286:6, s. 595-608
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Autoimmune disease is one of the leading causes of morbidity and mortality worldwide. In Addison's disease, the adrenal glands are targeted by destructive autoimmunity. Despite being the most common cause of primary adrenal failure, little is known about its aetiology.METHODS: To understand the genetic background of Addison's disease, we utilized the extensively characterized patients of the Swedish Addison Registry. We developed an extended exome capture array comprising a selected set of 1853 genes and their potential regulatory elements, for the purpose of sequencing 479 patients with Addison's disease and 1394 controls.RESULTS: We identified BACH2 (rs62408233-A, OR = 2.01 (1.71-2.37), P = 1.66 × 10(-15) , MAF 0.46/0.29 in cases/controls) as a novel gene associated with Addison's disease development. We also confirmed the previously known associations with the HLA complex.CONCLUSION: Whilst BACH2 has been previously reported to associate with organ-specific autoimmune diseases co-inherited with Addison's disease, we have identified BACH2 as a major risk locus in Addison's disease, independent of concomitant autoimmune diseases. Our results may enable future research towards preventive disease treatment.
|
|
| 7. |
- Farias, Fabiana H. G., et al.
(författare)
-
A rare regulatory variant in the MEF2D gene affects gene regulation and splicing and is associated with a SLE sub-phenotype in Swedish cohorts
- 2019
-
Ingår i: European Journal of Human Genetics. - : Springer Science and Business Media LLC. - 1018-4813 .- 1476-5438. ; 27, s. 432-441
-
Tidskriftsartikel (refereegranskat)abstract
- Systemic lupus erythematosus (SLE) is an autoimmune disorder with heterogeneous clinical presentation and complex etiology involving the interplay between genetic, epigenetic, environmental and hormonal factors. Many common SNPs identified by genome wide-association studies (GWAS) explain only a small part of the disease heritability suggesting the contribution from rare genetic variants, undetectable in GWAS, and complex epistatic interactions. Using targeted re-sequencing of coding and conserved regulatory regions within and around 215 candidate genes selected on the basis of their known role in autoimmunity and genes associated with canine immune-mediated diseases, we identified a rare regulatory variant rs200395694:G > T located in intron 4 of the MEF2D gene encoding the myocyte-specific enhancer factor 2D transcription factor and associated with SLE in Swedish cohorts (504 SLE patients and 839 healthy controls, p = 0.014, CI = 1.1-10). Fisher's exact test revealed an association between the genetic variant and a triad of disease manifestations including Raynaud, anti-U1-ribonucleoprotein (anti-RNP), and anti-Smith (anti-Sm) antibodies (p = 0.00037) among the patients. The DNA-binding activity of the allele was further studied by EMSA, reporter assays, and minigenes. The region has properties of an active cell-specific enhancer, differentially affected by the alleles of rs200395694:G > T. In addition, the risk allele exerts an inhibitory effect on the splicing of the alternative tissue-specific isoform, and thus may modify the target gene set regulated by this isoform. These findings emphasize the potential of dissecting traits of complex diseases and correlating them with rare risk alleles with strong biological effects.
|
|
| 8. |
- Houtman, Miranda, et al.
(författare)
-
T cells are influenced by a long non-coding RNA in the autoimmune associated PTPN2 locus
- 2018
-
Ingår i: Journal of Autoimmunity. - : ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD. - 0896-8411 .- 1095-9157. ; 90, s. 28-38
-
Tidskriftsartikel (refereegranskat)abstract
- Non-coding SNPs in the protein tyrosine phosphatase non-receptor type 2 (PTPN2) locus have been linked with several autoimmune diseases, including rheumatoid arthritis, type I diabetes, and inflammatory bowel disease. However, the functional consequences of these SNPs are poorly characterized. Herein, we show in blood cells that SNPs in the PTPN2 locus are highly correlated with DNA methylation levels at four CpG sites downstream of PTPN2 and expression levels of the long non-coding RNA (IncRNA) LINC01882 downstream of these CpG sites. We observed that LINC01882 is mainly expressed in T cells and that anti-CD3/CD28 activated naive CD4(+) T cells downregulate the expression of LINC01882. RNA sequencing analysis of LINC01882 knockdown in Jurkat T cells, using a combination of antisense oligo-nucleotides and RNA interference, revealed the upregulation of the transcription factor ZEB1 and kinase MAP2K4, both involved in IL-2 regulation. Overall, our data suggests the involvement of LINC01882 in T cell activation and hints towards an auxiliary role of these non-coding SNPs in autoimmunity associated with the PTPN2 locus.
|
|
| 9. |
- Lindahl, Hannes, et al.
(författare)
-
IL-22 Binding Protein Promotes the Disease Process in Multiple Sclerosis
- 2019
-
Ingår i: Journal of Immunology. - : AMER ASSOC IMMUNOLOGISTS. - 0022-1767 .- 1550-6606. ; 203:4, s. 888-898
-
Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies have mapped the specific sequence variants that predispose for multiple sclerosis (MS). The pathogenic mechanisms that underlie these associations could be leveraged to develop safer and more effective MS treatments but are still poorly understood. In this article, we study the genetic risk variant rs17066096 and the candidate gene that encodes IL-22 binding protein (IL-22BP), an antagonist molecule of the cytokine IL-22. We show that monocytes from carriers of the risk genotype of rs17066096 express more IL-22BP in vitro and cerebrospinal fluid levels of IL-22BP correlate with MS lesion load on magnetic resonance imaging. We confirm the pathogenicity of IL-22BP in both rat and mouse models of MS and go on to suggest a pathogenic mechanism involving lack of IL-22-mediated inhibition of T cell-derived IFN-gamma expression. Our results demonstrate a pathogenic role of IL-22BP in three species with a potential mechanism of action involving T cell polarization, suggesting a therapeutic potential of IL-22 in the context of MS.
|
|
| 10. |
- Odqvist, Lina, et al.
(författare)
-
Genetic variations in A20 DUB domain provide a genetic link to citrullination and neutrophil extracellular traps in systemic lupus erythematosus
- 2019
-
Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 78:10, s. 1363-1370
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: Genetic variations in TNFAIP3 (A20) de-ubiquitinase (DUB) domain increase the risk of systemic lupus erythematosus (SLE) and rheumatoid arthritis. A20 is a negative regulator of NF-κB but the role of its DUB domain and related genetic variants remain unclear. We aimed to study the functional effects of A20 DUB-domain alterations in immune cells and understand its link to SLE pathogenesis. Methods: CRISPR/Cas9 was used to generate human U937 monocytes with A20 DUB-inactivating C103A knock-in (KI) mutation. Whole genome RNA-sequencing was used to identify differentially expressed genes between WT and C103A KI cells. Functional studies were performed in A20 C103A U937 cells and in immune cells from A20 C103A mice and genotyped healthy individuals with A20 DUB polymorphism rs2230926. Neutrophil extracellular trap (NET) formation was addressed ex vivo in neutrophils from A20 C103A mice and SLE-patients with rs2230926. Results: Genetic disruption of A20 DUB domain in human and murine myeloid cells did not give rise to enhanced NF-κB signalling. Instead, cells with C103A mutation or rs2230926 polymorphism presented an upregulated expression of PADI4, an enzyme regulating protein citrullination and NET formation, two key mechanisms in autoimmune pathology. A20 C103A cells exhibited enhanced protein citrullination and extracellular trap formation, which could be suppressed by selective PAD4 inhibition. Moreover, SLE-patients with rs2230926 showed increased NETs and increased frequency of autoantibodies to citrullinated epitopes. Conclusions: We propose that genetic alterations disrupting the A20 DUB domain mediate increased susceptibility to SLE through the upregulation of PADI4 with resultant protein citrullination and extracellular trap formation.
|
|
