Recent progress in genome editing for gene therapy applications: the French perspective.

Recent advances in genome editing tools, especially the novel developments in the clustered regularly interspaced short palindrome repeats associated protein (CRISPR/Cas)-derived editing machinery have revolutionized not only basic science but, importantly, also the gene therapy field. Their flexibility and ability to introduce precise modifications in the genome in order to disrupt or correct genes or insert expression cassettes in safe harbors in the genome underlines their potential applications as a medicine of the future to cure many genetic diseases. In this review, we give an overview of the recent progress made by French researchers in the field of therapeutic genome editing while putting their work in the general context of advances made in the field. We focus on recent hematopoietic stem cell gene editing strategies for blood diseases affecting the red blood cells or blood coagulation as well as lysosomal storage diseases. We report on a genome editing based therapy for a muscular dystrophy and the potency of T cell gene editing to increase anti-cancer activity of chimeric antigen receptor (CAR) T cells to combat cancer. We will also discuss technical obstacles and side-effects such as unwanted editing activity that need to be surmounted on the way towards a clinical implementation of genome editing. We propose here improvements developed today, including by French researchers to overcome the editing related genotoxicity and improve editing precision by the use of novel recombinant nuclease-based systems such as nickases, base editors and prime editors. Finally, a solution is proposed to resolve the cellular toxicity induced by the systems employed for gene editing machinery delivery.