A minigene-constructs was generated to efficiently model the 3272-26A>G CFTRand 3849+10kbC>T splicing defects. The analyses performed with the minigene models, either transiently or stably transfected in HEK293 cells and Caco-2 cells, in primary airway cells and in patients derived organoids, revealed that the AsCas12a in combination with a selected guide RNA is a highly efficient and precise technique to repair the splicing defects. These results demonstrate that AsCas12a in combination with a single sgRNA efficiently rescues endogenous CFTR function in patient’s intestinal organoids, which are recognised as a highly valuable preclinical model to predict ex vivo any success of therapeutic treatment in human patients. These results provide an important milestone towards the development of a successful gene therapy clinical approach for the treatment of splicing defects in Cystic Fibrosis.

Congress abstracts

• Maule G, Ramalho A, Arosio D et al. Genome editing strategies to restore altered splicing events in cystic fibrosis, 12th European CF Young Investigators’ Meeting (EYIM), Paris, Institute Pasteur, February 21-23, 2018 (best oral presentation)
• Maule G, Casini A, Montagna C et al. Permanent repair of splicing defect in cystic fibrosis through AsCas12a genome editing, European Society of Gene and Cell Therapy (ESGCT) – Changing Modern Medicine: Stem Cells & Gene, Lousanne, Switzerland, October 16-19, 2018