Preclinical characterization of antagomiR-218 as a potential treatment for myotonic dystrophy

Authors
E Cerro-Herreros, I González-Martínez, N Moreno

Lab
Translational Genomics Group. University Research Institute for Biotechnology and Biomedicine, Universidad de Valencia, Valencia, Spain

Journal
Molecular Therapy-Nucleic Acids

Abstract
Myotonic dystrophy type 1 (DM1) is a rare neuromuscular disease caused by expansion of unstable CTG repeats in a non-coding region of the DMPK gene. CUG expansions in mutant DMPK transcripts sequester MBNL1 proteins in ribonuclear foci. Depletion of this protein is a primary contributor to dis ease symptoms such as muscle weakness and atrophy and myotonia, yet upregulation of endogenous MBNL1 levels may compensate for this sequestration. Having previously demonstrated that antisense oligonucleotides against miR218 boost MBNL1 expression and rescue phenotypes in disease models, here we provide preclinical characterization of an anta gomiR-218 molecule using the HSALR mouse model and patient-derived myotubes. In HSALR, antagomiR-218 reached 40–60 pM 2 weeks after injection, rescued molecular and functional phenotypes in a dose- and time-dependent manner, and showed a good toxicity profile after a single subcutaneous administration. In muscle tissue, antagomiR rescued the normal subcellular distribution of Mbnl1 and did not alter the proportion of myonuclei containing CUG foci. In patient-derived cells, antagomiR-218 improved defective fusion and differentiation and rescued up to 34% of the gene expression alterations found in the transcriptome of patient cells. Importantly, miR-218 was found to be upregulated in DM1 muscle biopsies, pinpointing this microRNA (miRNA) as a relevant therapeutic target.

BIOSEB Instruments Used:
Grip strength test (BIO-GS3)