PRE-CLINICAL EVALUATION OF BIOCOMPATIBLE NANOPARTICLES AS DELIVERY SYSTEM OF 20-METHYL-PHOSPHOROTHIOATE (2OMePS) ANTISENSE OLIGORIBONUCLEOTIDES FOR EXON SKIPPIN- MEDIATED DYSTROPHIN IN RESTORATION

Duchenne muscular dystrophy (DMD) is a severe hereditary childhood neuromuscular disease caused by mutations in the DMD gene and resulting in the absence of the dystrophin protein. The most promising therapy for DMD is based on antisense oligoribonucleotides (AONs), RNA molecules which have the capacity to skip a target exon and thereby to correct the molecular defect resulting in the synthesis of a largely functional dystrophin protein. A pilot trial in vivo by using a naked chemical modified antisense oligoribonucleotides (2OMePs) recently showed the effectiveness of the approach. Other PhaseI/II trials using chemical different antisense are ongoing. One of the difficulties of developing antisense drugs is delivering it to the target gene before the drug degrades. We demonstrated in the mdx animal model that a novel biocompatible type of nanoparticle (named T1, with a core of polymethilmethacrylate) was able to bind and convey 2OMePS antisense oligoribonucleotides (AONs) and induced dystrophin restoration in body wide muscles. The aim of our project is to study if nanoparticle-antisense complex might represent a suitable, safe and efficacious compound to be possibly transferred into Duchenne muscular dystrophy therapies. To identify the best nanoparticle- AONs compound we will investigate in the mdx animal model other nanoparticles types with higher AONs loading capacity. We will try and compare different types of administration, including oral, and we will study the optimal AONs concentration able to have a sustained therapeutic effect. We will utilize pharmacokinetic studies to identify the clearance modes and to investigate possible side effects of nanoparticle-AONs complexes as well. Furthermore we will evaluate the safety aspects of this novel compounds in regard to transcription and expression of others sarcolemma proteins.