Targeting RyR Activity Boosts Antisense Exon 44 and 45 Skipping in Human DMD Skeletal or Cardiac Muscle Culture Models

Florian Barthélémy; Richard T Wang; Christopher Hsu; Emilie D Douine; Eugene E Marcantonio; Stanley F Nelson; M Carrie Miceli

doi:10.1016/j.omtn.2019.09.020

Targeting RyR Activity Boosts Antisense Exon 44 and 45 Skipping in Human DMD Skeletal or Cardiac Muscle Culture Models

Mol Ther Nucleic Acids. 2019 Dec 6:18:580-589. doi: 10.1016/j.omtn.2019.09.020. Epub 2019 Sep 28.

Authors

Florian Barthélémy¹, Richard T Wang², Christopher Hsu¹, Emilie D Douine², Eugene E Marcantonio³, Stanley F Nelson⁴, M Carrie Miceli⁵

Affiliations

¹ Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine, and College of Letters and Sciences, University of California, Los Angeles, Los Angeles, CA, USA; Center for Duchenne Muscular Dystrophy, University of California, Los Angeles, Los Angeles, CA, USA.
² Center for Duchenne Muscular Dystrophy, University of California, Los Angeles, Los Angeles, CA, USA; Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA.
³ ARMGO Pharma, Inc., Ardsley, NY 10502, USA.
⁴ Center for Duchenne Muscular Dystrophy, University of California, Los Angeles, Los Angeles, CA, USA; Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA; Eli & Edythe Broad Center of Regenerative Medicine & Stem Cell Research, University of California Los Angeles, Los Angeles, CA, USA; Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA, USA; Department of Pathology and Laboratory Medicine, University of California Los Angeles, Los Angeles, CA, USA.
⁵ Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine, and College of Letters and Sciences, University of California, Los Angeles, Los Angeles, CA, USA; Center for Duchenne Muscular Dystrophy, University of California, Los Angeles, Los Angeles, CA, USA; Eli & Edythe Broad Center of Regenerative Medicine & Stem Cell Research, University of California Los Angeles, Los Angeles, CA, USA; Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA, USA; Department of Pathology and Laboratory Medicine, University of California Los Angeles, Los Angeles, CA, USA. Electronic address: cmiceli@ucla.edu.

Abstract

Systemic delivery of antisense oligonucleotides (AO) for DMD exon skipping has proven effective for reframing DMD mRNA, rescuing dystrophin expression, and slowing disease progression in animal models. In humans with Duchenne muscular dystrophy treated with AOs, low levels of dystrophin have been induced, and modest slowing of disease progression has been observed, highlighting the need for improved efficiency of human skipping drugs. Here, we demonstrate that dantrolene and Rycals S107 and ARM210 potentiate AO-mediated exon skipping of exon 44 or exon 45 in patient-derived myotube cultures with appropriate mutations. Further, dantrolene is shown to boost AO-mediated exon skipping in patient-derived, induced cardiomyocyte cultures. Our findings further validate the ryanodine receptors (RyR) as the likely target responsible for exon skip boosting and demonstrate potential applicability beyond exon 51 skipping. These data provide preclinical support of dantrolene trial as an adjuvant to AO-mediated exon-skipping therapy in humans and identify a novel Rycal, ARM210, for development as a potential exon-skipping booster. Further, they highlight the value of mutation-specific DMD culture models for basic discovery, preclinical drug screening and translation of personalized genetic medicines.

Keywords: ARM210; Duchenne muscular dystrophy; armgo; combination therapy; dantrolene; dystrophin; exon skipping; muscle; therapy.