Project description:<p>Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that can have debilitating effects on multiple organ systems. In SLE, the pivotal immunologic disturbance is the formation of autoantibodies directed against nuclear and cellular antigens. These autoantibodies are associated with specific organ manifestations. Our previous work has shown that certain single nucleotide polymorphisms (SNPs) are associated with the production of SLE-related autoantibodies. However, these genetic associations do not completely explain autoantibody development in SLE. Therefore, we examined whether epigenetic factors such as DNA methylation may be associated with the development of SLE-related autoantibodies.</p> <p>In this study, we examined whether differential DNA methylation is associated with anti-dsDNA, anti-SSA/Ro, anti-Smith, and anti-RNP autoantibodies. Using the Illumina HumanMethylation450 Beadchip, over 450,000 DNA methylation sites were characterized in 325 female SLE cases of European descent. Using a multivariable regression analyses, the methylation status of 16 CpG sites in 11 genes was found to be associated with the SLE-related autoantibodies under study. This study shows that epigenetic factors are associated with autoimmune disease phenotypes, and epigenetic studies are a complementary method to genetic association studies for understanding the biologic mechanisms contributing to autoimmune disease.</p>
Project description:Study to investigate the role of histone residues H3K4 and H3K36 for gene expression, histone localization and neuronal lineage specification by mutation of K4 and K36 in H3.3 to alanine. Histone variant H3.3 differs from the canonical H3.1/H3.2 by only 4 to 5 amino acids, which are necessary for nucleosome assembly independent of DNA replication, and is encoded by two gene copies. Complete loss of the two H3.3 genes (H3f3a and H3f3b) leads to embryonic lethality while single gene knockout yields viable mice. We used CRISPR-Cas9 to delete H3f3a and introduce homozygous point-mutations into H3f3b, thus ensuring that the entire pool of H3.3 protein carries the mutation of interest. We differentiated H3.3ctrl (H3f3a knock-out; H3f3b wild type), H3.3K4A mutant (H3f3a knock-out; H3f3b K4A) and H3.3K36A mutant (H3f3a knock-out; H3f3b K36A) ESCs into glutamatergic neurons. Genomic localization of H3.3 protein was determined by ChIP-Sequencing in ESCs (D0). Histone modifications patterns of H3K4me1, H3K4me3 and H3K27ac were measured by ChIP-Sequencing in ESCs (D0) to assess the impact of the H3.3K4A mutation on the epigenetic landscape. Levels of H3K36me3 were measured by ChIP-Sequencing in WT and H3.3K36A mutant ESCs (D0), NPCs (D8) and neurons (D12) to assess the impact of the H3.3K36A mutation on H3K36me3 levels in development.