PROJECT SUMMARY/ABSTRACT
Duchenne muscular dystrophy (DMD) is a fatal X-linked muscle degenerative disease. Children with DMD
become restricted to wheelchairs within the first decade of their lives and die within the third. There is no effective
treatment available for this devastating disease. Key myogenic processes in DMD pathophysiology at the
molecular level are not completely understood, hindering the development of therapies for DMD. To fill this
knowledge gap, we have been investigating whether an emerging mode of post-transcriptional gene regulation,
known as epitranscriptomics, plays a role in DMD pathogenesis. Epitranscriptomics is a dynamic process that
regulates RNA stability, splicing, and translation by reversible chemical modifications of mRNAs. N6-
methyladenosine (m6A) is the most abundant epitranscriptomic mark. The m6A marks are installed by
methyltransferase like 3 (METTL3) and methyltransferase like 14 (METTL14) and erased by fat mass and
obesity-associated (FTO) and alkylation repair homolog 5 (ALKBH5). Specific reader proteins selectively
recognize m6A-modified mRNAs and control their fates. Our recent findings revealed that m6A mRNA methylation
regulates myogenesis in DMD and that levels of the m6A writers, erasers, and m6A marks are tightly regulated
during myoblast differentiation, muscle regeneration, and in DMD. These studies suggest that m6A mRNA
methylation plays a pivotal role in DMD pathophysiology. Here, we propose to gain a deeper mechanistic insight
into m6A mRNA methylation in DMD. We will perform a transcriptome-wide analysis to map m6A-modified
mRNAs (methylome) in skeletal muscle stem cells (MuSCs), primary myoblasts, and skeletal muscle of a well-
established mdx mouse model of DMD and its counterpart healthy mice. We will also map the m6A methylome
in DMD patient-derived and healthy myoblasts to extend our conclusions to a more clinically relevant model
system. We will mechanistically characterize a select subset of prioritized m6A target mRNAs, both previously
associated with DMD, as well as the novel, to establish their link to muscle degeneration in DMD. Our proposed
research will make a significant impact by revealing transcriptome-wide m6A target mRNAs in DMD and provide
insights into DMD pathophysiology incurred by the dysregulation of this novel mechanism.