Antisense Oligonucleotides Targeting an LDLR Regulatory RNA Increase LDLR Expression and Reduce LDL-cholesterol in Vivo

Regulatory RNAs (regRNAs) are non-coding RNAs expressed from promoters and enhancers that modulate gene transcription. Targeting regRNAs with antisense oligonucleotides (ASOs) can increase transcription and presents a potential therapeutic strategy to restore expression in haploinsufficient diseases. This approach requires high-quality regRNA maps, identification of ASOs targeting actionable sequences, and translation of efficacy to relevant animal models. Here, we describe this approach for human low-density lipoprotein receptor ( LDLR ). We characterized LDLR regRNAs in HepG2 cells and human liver using epigenomic mapping and regRNA Capture-seq, and designed ASOs targeting these regRNAs. Several ASOs increased LDLR expression in cells and a lead was evaluated for efficacy in a humanized liver mouse model. ASO administration increased human LDLR mRNA and protein, while lowering LDL-cholesterol in plasma. These data provide a framework for the discovery and translation of ASOs that increase gene expression as a potential therapeutic approach for the treatment of haploinsufficient diseases.