Abstract

RNA splicing is an essential step in producing mature messenger RNA (mRNA) and other RNA species. Exon skipping involves the removal of certain exons from mRNAs during splicing.1 Harnessing RNA splicing modifiers that induce exon skipping is promising for the treatment of diseases caused by aberrant splicing. Several antisense oligonucleotide splicing modifiers were approved by the U.S. Food and Drug Administration (FDA) for the treatment of spinal muscular atrophy (SMA) and Duchenne muscular dystrophy (DMD). Recently, a small-molecule splicing modifier, Risdiplam, was also approved for the treatment of SMA, highlighting small molecules as important warheads in the arsenal for regulating RNA splicing. The cellular targets of these approved drugs are all mRNA precursors (pre-mRNAs) in human cells.2

Here we describe the successful development of 1536 well minigene luciferase reporter gene assays for a novel target to identify small molecules that induce exon skipping events. We performed pilot screening on subsets comprising ~20 000 compounds demonstrating the delivery of a robust assay format suitable for primary screening and the first AstraZeneca small molecule HTS targeting RNA.

References

1. Matsuo M. Antisense Oligonucleotide-Mediated Exon-skipping Therapies: Precision Medicine Spreading from Duchenne Muscular Dystrophy. JMA J. 2021;4(3):232-240.

2. Tang et al. (2021) RNA-Targeting Splicing Modifiers: Drug Development and Screening Assays, Molecules 2021, 26, 2263