RNA-seq of muscle reveals transcriptomic changes associated with improved pathophysiology of mdx mice harboring genetic deletion of miR-146a


Topic:

Translational Research

Poster Number: P148

Author(s):

Dove Enicks, MS, Center for Inherited Myology Research/ Virginia Commonwealth University, Nikki McCormack, PhD, Children’s National Research Institute, Marina Provenzano, PhD, 3Center for Inherited Myology Research, Virginia Commonwealth University, Richmond VA 23298, USA. 4D, Melissa A. Hale, PhD, 3Center for Inherited Myology Research, Virginia Commonwealth University, Richmond VA 23298, USA. 4D, Christopher Heier, PhD, Center for Inherited Myology Research/Virginia Commonwealth University School of Medicine, Alyson A Fiorillo, PhD, Center for Inherited Myology Research/ Virginia Commonwealth University

Duchenne muscular dystrophy (DMD) is a progressive X-linked neurodegenerative disease caused by loss-of-function mutations in the dystrophin gene, resulting in the complete absence of dystrophin protein. The molecular mechanisms are not fully known, but evidence supporting miR-146a as a suspected driver of chronic inflammation in DMD muscles has been observed as one aspect, such as elevated levels of miR-146a in the muscles of DMD patients and in DMD model mice (mdx). To investigate the role of miR-146a in DMD pathophysiology, mdx mice with genetic deletion of miR-146a were generated (termed mdx-146aX) along with wild-type (WT) containing a double knock-out (WT-146a-/-) serving as a control for background. We performed bulk RNA sequencing of the tibialis anterior muscle of WT, WT-146a-/-, mdx, and mdx-146aX mice. Differential gene expression analysis, gene ontology (GO) analyses, and various gene signatures were utilized to demonstrate a trend of genetic expression towards WT in mdx-146aX muscles. Notably we identified genes involved in interferon-g signaling (Irga6/Iigp), Wnt signaling (Sfrp1), and muscle regeneration (Pcdhb7) that were elevated in mdx and reduced towards WT in mdx-146aX. mdx muscles also showed reductions in genes involved in mitochondrial biogenesis (Mrpl55) and muscle differentiation (Ckdl1) that were increased towards WT levels in mdx-146aX. Additionally, we analyzed an inflammatory gene signature and a myonuclear cell signature further supporting a shift towards WT in mdx-146aX mice. Together, these data provide more context to previously observed improved functionality of mdx-146aX mice and suggest miR-146a could serve as a potential focus for therapeutics considering its role in DMD pathophysiology.