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Epigenetic regulation of IBD-associated fibrosis: potential for novel anti-fibrotic therapies Tammy Sadler1,2, Angela Ting3, Yaomin Xu4, Xiuli Liu5, Eleni Stylianou1,2 1Department of Pathobiology, Lerner Research Institute, and 2Department of Gastroenterology and Hepatology, Digestive Disease Institute, 3Genomic Medicine Institute, 4Department of Quantitative Health Sciences, 5Department of Anatomic Pathology. Cleveland Clinic Foundation, Cleveland, USA Inflammatory Bowel Disease – etiology? Environmental factors Genetic susceptibility Abnormal interaction of commensal gut flora, epithelial barrier and innate immunity Crohn’s Disease Inflammation of small bowel & colon: transmural EPIGENETICS? Increased matrix depostion e.g.Type I collagen (COL1A1, COL1A2) FIBROSIS Intestinal inflammation and fibrosis in IBD Gut flora Epithelium Endogenous signals Apoptotic & necrotic epithelial cells GUT LUMEN Mucosal innate immune cells Cytokines, chemokines e.g TNFa, IL-8, TGFb, IL-1b, IL-17 Epithelial barrier dysfunction Cytokines SUBMUCOS A Endothelial cells TYPE I COLLAGEN FIBROSIS Mesenchymal cells/fibroblasts/myofibrobla sts Epigenetics •Heritable changes in phenotype that are independent of changes to the DNA sequence •2 examples: Histone modifications and DNA methylation • Epigenetic mechanisms determine whether a gene is silenced or activated and allows the cell to adapt to environmental cues. • Epigenetics bridges the gap between genotype and environment Epigenetic regulation of gene transcription IL-1b LPS K9me H3 K27me TNF-a Corepressors H4 DNA methylation K4me H3 Kac Histone-modified, remodelled, decondensed promoter (euchromatin) H4 K4me H3 Kac H4 Repressed, histone/DNA methylated promoter: condensed chromatin (heterochromatin) Coactivators RNA Pol II Accessible, transcriptionally active promoter Scarpa & Stylianou Inflamm Bowel Dis 2012 Clinical Significance •Epigenetic modifications required for Type I collagen gene expression and a fibrotic DNA methylome or epigenotype for CD could have diagnostic and prognostic utility. •New mechanistic insights into clinically relevant mechanisms of disease pathogenesis could be provided. •The conceptual framework for identification of therapeutic targets and selective and efficacious antifibrotic "epi-pharmaceuticals” that could prevent or treat fibrosis. Specific histone modifications are associated with induction of COL1A2 gene expression in intestinal EndoMT A IL1b TGFb TNFa 5 days B IL1b TGFb Ac 8 Ac Ac 12 16 H4 Ac 8 Ac Ac 12 16 H4 MeMe MeMe 9 Ac Ac 5 8 Ac Ac 12 16 TNFa H3 9 H4 Ac Ac 5 8 Ac Ac 12 16 H3 H4 H3 H3 H4 H4 H3 H3 16 days C Cytokines removed after 16 days + 10 day washoff Ac 16 -1599bp Sadler et al Inflamm Bowel Dis 2013 in press COL1A2 -25bp COL1A2 COL1A2 Hypothesis and Aims Fibrosis-specific epigenetic signatures occur in the fibrotic intestine in IBD. This hypothesis will be tested by 2 specific aims: Aim 1. Determine the fibrosis-specific histone modification signature in human fibrotic intestine in IBD in vivo. Aim 2. Identify the fibrosis-specific DNA methylome that defines human intestinal fibrogenesis in IBD in vivo. Research plan • Year 1 •Collect age and gender matched normal control and CD fibrotic tissue specimens •Optimize conditions for ChIP of tissue •Establish conditions for isolation of fresh human fibroblasts •Demonstrate feasibility of performing epigenetic analysis in fresh HIF •Year 2 •ChIP assays of tissue and fresh HIF to define type I collagen specific histone modification signature •Employ MBD-isolated genome sequencing (MiGS) to profile changes in DNA methylation in human fibroblasts from fibrotic intestine. •Integrate methylome with fibrotic transcriptome Intestinal tissue specimens procured during year 1 Tissue source Diagnosis Number of specimens Colon Diverticular disease 7 Polyps 3 UC inflamed 8 CD fibrotic 10 CD inflamed 5 Polyps 1 Ileocolic anastamosis 1 CD fibrotic 8 CD inflamed 4 Ileum