Project description:This study investigate the non-MHC association/interaction in Swedish IgAD patients carrying different MHC susceptibility haplotypes.
Project description:A genetic study of the PRF1 gene has shown association of several polymorphisms with multiple sclerosis (MS). Haplotype analysis identified risk haplotypes strongly associated with male patients having the primary-progressive form of MS (PPMS). Gene expression microarrays were performed in 10 male PPMS patients carrying the risk (n=6) and protective haplotypes (n=4) in order to identify pathways associated with the risk haplotypes. Pathway analysis revealed overrepresentation of the cell killing gene ontology category among down-regulated genes in patients carrying risk haplotypes compared with patients carrying protective haplotypes.
Project description:A genetic study of the PRF1 gene has shown association of several polymorphisms with multiple sclerosis (MS). Haplotype analysis identified risk haplotypes strongly associated with male patients having the primary-progressive form of MS (PPMS). Gene expression microarrays were performed in 10 male PPMS patients carrying the risk (n=6) and protective haplotypes (n=4) in order to identify pathways associated with the risk haplotypes. Pathway analysis revealed overrepresentation of the cell killing gene ontology category among down-regulated genes in patients carrying risk haplotypes compared with patients carrying protective haplotypes. Number of samples analyzed: 10 Protective haplotype samples: UOM982, EMA1473, MMC-998, CDP1842 Risk haplotype samples: UUS1554, RAU1550, RPS1011, AGS1013, PFB1530, MGA1014
Project description:HLA-DRB1 alleles have been associated with several autoimmune diseases. In anti-citrullinated protein antibody positive rheumatoid arthritis (ACPA-positive RA), HLA-DRB1 shared epitope (SE) alleles are the major genetic risk factors. In order to investigate whether expression of different alleles of major histocompatibility complex (MHC) Class II genes influence functions of immune cells, we investigated transcriptomic profiles of a variety of immune cells from healthy individuals carrying different HLA-DRB1 alleles. Sequencing libraries from peripheral blood mononuclear cells, CD4+ T cells, CD8+ T cells, and CD14+ monocytes of 32 genetically pre-selected healthy female individuals were generated, sequenced and reads were aligned to the standard reference. For the MHC region, reads were mapped to available MHC reference haplotypes and AltHapAlignR was used to estimate gene expression. Using this method, HLA-DRB and HLA-DQ were found to be differentially expressed in different immune cells of healthy individuals as well as in whole blood samples of RA patients carrying HLA-DRB1 SE-positive versus SE-negative alleles. In contrast, no genes outside the MHC region were differentially expressed between individuals carrying HLA-DRB1 SE-positive and SE-negative alleles. Existing methods for HLA-DR allele-specific protein expression were evaluated but were not mature enough to provide appropriate complementary information at the protein level. Altogether, our findings suggest that immune effects associated with different allelic forms of HLA-DR and HLA-DQ may be associated not only with differences in the structure of these proteins, but also with differences in their expression levels.
Project description:This experiment accompanies the main analysis using a custom MHC array to define the first high-resolution, strand-specific transcriptional map of the MHC, defining differences in gene expression for three common haplotypes associated with autoimmune disease. Unstimulated samples for each haplotype were hybridised to Affymetrix Human Exon 1.0 ST arrays as well the custom MHC array. Exon array data were used to assess the concordance of signal obtained from the two platforms and to investigate the extent of alternative splicing in the MHC, and how it compares to the rest of the genome. Lymphoblastoid cell lines carrying three common autoimmunity haplotypes (COX, PGF, QBL) were analysed in triplicate using the Affymetrix Human Exon 1.0 ST Array.
Project description:The human MHC is a paradigm for genomics, showing striking association with disease but functional variants remain largely unresolved. Using an original hybrid microarray (containing tiling and junction probes) for the MHC and accounting for known sequence diversity, we have drawn the first high-resolution, strand-specific transcriptional map of the MHC, defining differences in gene expression for three common haplotypes associated with autoimmune disease. In total, 6% of the MHC is transcribed with one transcript per 1.4kb, including previously unrecognized intergenic transcription. The distributions of differentially expressed probes and polymorphisms between haplotypes are significantly correlated, arguing for cis effects. Haplotype-specific transcription involved 96 differentially expressed genes, including ZFP57, which was validated in a cohort of healthy volunteers, while 526 exons show haplotypic differences. We also find splicing events are significantly more extensive in the MHC than in the rest of the genome. This study marks a new step in immunogenetics. The results files (.wig and .gff) contain tiling data for both the shared-path and the alternate paths (shared and haplotype-specific) , defining transcriptional activity across the entire MHC region in each sample. Lymphoblastoid cell lines carrying three common autoimmunity haplotypes (COX, PGF, QBL) were analysed in triplicate using the custom MHC array, under both unstimulated and stimulated (200nM PMA and 125nM ionomycin for 6 hours) conditions.
Project description:To explore the effect of human MHC haplotype on gene expression phenotype across the MHC, we examine the MHC transcriptomic landscape at the haplotype-specific resolution for three prominent MHC haplotypes (A2-B46-DR9, A33-B58-DR3 and A1-B8-DR3) derived from the RNA-sequencing of MHC-homozygous B-LCLs. We demonstrate that MHC-wide gene expression pattern is dictated by the underlying MHC haplotype and identify 37 differentially expressed genes among the haplotypes.
Project description:A progressive increase in the breadth and specificity of autoantibodies over time, termed epitope spreading, drives pathogenic targeting of an ever-widening repertoire of self-components in many autoimmune diseases. Ostensibly, this progressive inclusion of additional B cell clones into an ongoing autoreactive response can occur through linked recognition, whereby proto-autoreactive B cells recognize distinct antigenic epitopes, which carry shared T cell epitopes. In a murine model displaying epitope spreading resembling that observed in systemic lupus erythematosus, we find that the epitope spreading process is compartmentalized by MHC. Antigen presentation by B cells carrying two MHC haplotypes can bridge the MHC barrier between two compartments of B cells that do not share MHC haplotypes, by communicating with two separate pools of MHC-restricted T cells. This leads to inclusion of distinct and diverse B cell reactivities in germinal centers. Our findings demonstrate a formidable capacity of B cells to drive the autoreactive response.
Project description:Background: Alopecia areata (AA) is considered a highly heritable, T-cell-mediated autoimmune disease of the hair follicle. However, no convincing susceptibility gene has yet been pinpointed in the major histocompatibility complex (MHC), a genome region known to be associated with AA as compared to other regions. Methods: We engineered mice carrying AA risk allele identified by haplotype sequencing for the MHC region using allele-specific genome editing with the CRISPR/Cas9 system. Finally, we performed functional evaluations in the mice and AA patients with and without the risk allele. Findings: We identified a variant (rs142986308, p.Arg587Trp) in the coiled-coil alpha-helical rod protein 1 (CCHCR1) gene as the only non-synonymous variant in the AA risk haplotype. Furthermore, mice engineered to carry the risk allele displayed a hair loss phenotype. Transcriptomics further identified CCHCR1 as a novel component interacting with hair cortex keratin in hair shafts. Both, these alopecic mice and AA patients with the risk allele displayed morphologically impaired hair and comparable differential expression of hair-related genes, including hair keratin and keratin-associated proteins (KRTAPs). Interpretation: Our results implicate CCHCR1 with the risk allele in a previously unidentified subtype of AA based on aberrant keratinization in addition to autoimmune events.
Project description:We adapted the widely used digestion of chromatin with micrococcal nuclease (MNase) followed by deep sequencing to the parasite Trypanosoma cruzi, which presents numerous singularities. In this work, we use the hybrid CL Brener strain carrying two set of chromosomes from two substantially different parental strains. The hybrid strain CL Brener is composed of the Esmeraldo-like and non Esmeraldo-like haplotypes. Additionally, part of the genome was not assembled into any of the haplotypes. Sometimes the community working in the field uses just one haplotype as reference genome for simplicity. In this work, we emphasize the importance of using its whole genome as a reference. Moreover, we extended our analysis to a clonal strain, Sylvio-X10.