Epigenetic editing: Towards sustained gene expression reprogramming in diseases

The reversible nature of epigenetic (mis)regulation, in contrast to genetic mutations, allows for the possibility of reverting abnormal patterns of gene expression at a molecular level. This thesis deals with the development of epigenetic editing tools in order to reprogram aberrantly expressed gene patterns in diseases. Epigenetic Editing consists of a DNA binding domain (Zinc finger, TALEs or CRISPR-Cas) linked to the catalytic domain of epigenetic enzymes. Furthermore, site-specific epigenetic editing provides the opportunity to study the regulation of gene expression. In this thesis, we addressed the possibility of achieving sustained gene expression modulation, by combining several epigenetic marks, and evaluating the role of chromatin microenvironment in this context. By using several DNA binding platforms fused to transcriptional activating epigenetic enzymes, we were able to show in different chromatin microenvironments, the possibility of achieving sustained gene expression reprogramming. Using this technique, we were also able to address the function and possible therapeutic use of several genes that are involved in diseases such as cancer and COPD. We used epigenetic editing to show that TCTN2 overexpression is a therapeutic target in cancer, and also to analyze the dual role of RASSF1 isoforms in the development of cancer. Furthermore, we were able to show that downregulation of a mucus production gene in cells might have therapeutic relevance for COPD. In conclusion, our approach has the potency to achieve gene expression reprogramming in diseases.