Epigenetic Therapy with Artifical Transcriptional Repressors

In biology, epigenetics refers to all those mechanisms that convey heritable change in genome function without alterations of the primary DNA sequence. They are mostly based on DNA methylation and post-transcriptional histone modifications associated with transcriptional suppression that are self-sustaining once they have been deposited on a chromatin domain. Current research is unraveling the composition and function of the molecular machineries recruited to chromatin to induce these repressive states, and the mechanisms that once established support their stability and conservation through cell generations. We are interested in developing a new approach to exogenously induce the assembly of such complexes at a predetermined locus of the genome and usurp its transcription suppressive activity to permanently silence gene with a negative role in human disease. The advantage of such “epigenetic” therapy would be that it does not require introducing mutations or breaks in the DNA, as it occurs with current approaches based on integrating vectors or engineered nucleases, thus potentially providing for a much safer strategy. Moreover, the hit and run nature of an epigenetic silencing induction complex lends itself to transient delivery of Artificial Transcriptional Repressors (ATRs), engineered protein made up of an effector repressive domain fused with an artificially redirected DNA binding domain specific for the target gene. We will model this approach in human cell lines and test its feasibility in clinically relevant human primary Hematopoietic Stem and Progenitor cells carrying within the genome reporter cassettes engineered with multiple binding sites for ATRs. Once we have establishes a proof-ofprinciple of the approach we will explore its efficiency on a human genetic disease.