Comprehensive Epigenetic Landscape of Rheumatoid Arthritis FLS

We characterized the epigenetic landscape of rheumatoid arthritis fibroblast-like synoviocytes (FLS) compared with osteoarthritis FLS. Multiple technologies were used, including ChIP-seq to assay H3K27ac, H3K4me1, H3K4me3, H3K36me3, H3K27me3, and H3K9me3, ATAC-seq for chromatin accessibility, the transcriptome by RNA-seq and whole genomie bisulfite sequencing for DNA methylation. Integrative analysis was performed using a novel unbiased method to identify regions of the genome that have similar epigenetic marks. The regions that distinguished RA and osteoarthritis cells were primarily located in active enhancers and promoters. The regions and genes identified included immunological pathways. In addition, some unexpected pathways, most notably "Huntington''s Disease Signaling", were discovered. The Huntington''s Disease pathway was biologically validated for Huntingtin-interacting protein-1, which regulated invasive behavior of FLS. For a complete description... (for more see dbGaP study page.)