Differential Myokine Expression in a Model for Myotonic Dystrophy Type I

By Huda Al-Bana, Maya Takashima, Grace Holcomb

Faculty Mentor: Professor Ginny Morriss

Myotonic dystrophy type 1 (DM1) is a multi-systemic disease resulting in severe muscle weakening and wasting. Skeletal muscle wasting is the predominant cause of morbidity and mortality and is responsible for 60% of DM1-associated deaths. DM1 is caused by CTG repeat expansion in the 3’ untranslated region of the dystrophia myotonica protein kinase (DMPK) gene. Myokines are proteins that are produced and released by muscle cells in response to muscular contractions. Previous studies indicated that myokine signaling is deregulated in a mouse model expressing expanded CUG repeat (CUGexp) RNA. The goal of this work was to assess muscle-specific differential expression of myokines in mice expressing CUGexp RNA, relative to non-CUGexp RNA expressing control mice. Previously published RNA-seq datasets were compared to determine which putative myokines, identified in skeletal muscle samples of healthy subjects, were differentially expressed in CUGexp expressing mice. Myokines that display significant differential expression at 6, 12, and 20 weeks of repeat expression include the Cx3cl1, Cxcl10, and Gdf5. Primers were designed customary for these genes and specified for regions with constitutive exons to allow consideration of overall expression levels. Primers were then optimized using RT-PCR. The developed primers will be used to validate differential expression levels of these myokines using quantitative RT-PCR. Validated myokines will be assessed in unaffected and DM1 human myoblast cell lines to determine the contribution of these myokines to the skeletal muscle phenotype in DM1.