G.P.45

The autosomal dominant centronuclear myopathy (AD-CNM) is a rare congenital myopathy defined by skeletal muscle weakness and characteristic histopathological changes. Heterozygous mutations in the DNM2 gene are associated with entire clinical spectrum of AD-CNM. DNM2 gene encodes dynamin 2 (DNM2), a large GTPase ubiquitously expressed and involved in membrane trafficking. A Knock-In mouse model (KI-Dnm2R465W) expressing the most frequent mutation found in patients has been recently developed in the laboratory. The heterozygous mice progressively develop a muscle phenotype which recapitulates many aspects of the human condition. The purpose of this project is to evaluate the therapeutic potential of DNM2-mRNA repair by Spliceosome-Mediated RNA Trans-splicing (SMarT) technology able to reprogram the 5′, 3′ or internal coding sequence of endogenous mRNA. We have shown that classical 3′ strategy cannot be considered as accurate therapeutic strategy regarding the toxic effect of the Pre-Transplicing Molecules (PTMs) leading to low rate of trans-splicing in vivo. Thus, we tested several alternative strategies in order to prevent this toxicity and enhance frequency of trans-splicing events. We finally succeeded to overcome the toxicity using a 5′ trans-splicing strategy and obtained hopeful results. Indeed, we detected trans-splicing events at mRNA and protein levels in vitro and in vivo.