Enhancer and super-enhancer landscape in polycystic kidney disease

Abstract

Widespread aberrant gene expression is pathological hallmark of polycystic kidney disease (PKD). Numerous pathogenic signaling cascades, including c-Myc, Fos, and Jun are transactivated. However, the underlying epigenetic regulators are poorly defined. Here we show that H3K27ac, a histone modification that marks active enhancers, is elevated in mouse and human ADPKD samples. Using comparative H3K27ac ChIP-Seq analysis, we mapped >16000 active intronic and intergenic enhancer elements in Pkd1-mutant mouse kidneys. We find that the cystic kidney epigenetic landscape resembles that of a developing kidney, and >90% of upregulated genes in Pkd1-mutant kidneys are co-housed with activated enhancers in the same topologically associated domains. Furthermore, we identify an evolutionarily-conserved enhancer cluster downstream of the c-Myc gene and super-enhancers flanking both Jun and Fos loci in mouse and human ADPKD models. Deleting these regulatory elements reduces c-Myc, Jun, or Fos abundance and suppresses proliferation and 3D cyst growth of Pkd1-mutant cells. Finally, inhibiting glycolysis and glutaminolysis or activating Ppara in Pkd1-mutant cells lowers global H3K27ac levels and on c-Myc enhancers. Thus, our work suggests that epigenetic rewiring mediates the transcriptomic dysregulation in PKD, and the regulatory elements can be targeted to slow cyst growth.