Identification of epigenetic regulators of fibrotic transformation in cardiac fibroblasts through bulk and single-cell CRISPR screens (RNA-seq)

Cardiac fibrosis is mediated by the persistent activity of myofibroblasts, which differentiate from resident cardiac fibroblasts in response to tissue damage and stress signals. The signaling pathways and transcription factors regulating fibrotic transformation have been thoroughly studied. By contrast, the roles of chromatin factors in fibroblast differentiation and their contribution to pathogenic cardiac fibrosis remain poorly understood. Here, we have combined bulk and single-cell CRISPR screens to characterize the roles of chromatin factors in ex vivo fibroblast differentiation. We uncover strong regulators of fibrotic states including Srcap and Tip60 chromatin remodelers, the NSL complex and the co-factors Hcfc1 and Wdr82. We confirm these factors are required for cellular processes underlying fibrosis including collagen synthesis and cell contractility. We use epigenetic profiling to demonstrate these chromatin factors facilitate the activity of pro-fibrotic transcription factors. Finally, using chemical perturbation in primary human cardiac fibroblasts we suggest Tip60 inhibition as a potential therapeutic approach for cardiac fibrosis.