Individual transcriptomic response to strength-training for myotonic dystrophy type 1 patients

Myotonic dystrophy type 1 (DM1), the most common form of adult-onset muscular dystrophy, is caused by a CTG expansion resulting in significant transcriptomic dysregulation that leads to muscle weakness and wasting. While strength training is clinically beneficial in DM1, molecular effects had not been studied. To determine whether training rescued transcriptomic defects, RNA-sequencing was performed on vastus lateralis samples from nine male DM1 patients before and after a 12-week strength training program and six male controls who did not undergo training. Differential gene expression and alternative splicing analysis were correlated with the one-repetition maximum strength evaluation method (leg extension, leg press, hip abduction, and squat). While training program-induced improvements in splicing were similar among most individuals, rescued splicing events varied considerably between individuals. Gene expression improvements were highly varied between individuals with the percentage of differentially expressed genes rescued after training strongly correlated with strength improvements. Evaluating transcriptome changes individually revealed responses to the training not evident from grouped analysis, likely due to disease heterogeneity and individual exercise response differences. Our analyses indicate that transcriptomic changes are associated with clinical outcomes in DM1 patients undergoing training and these changes are often specific to the individual and should be analyzed accordingly. Overall design: 9 male DM1 patients had quadriceps muscle biopsies taken before and after a 12-week strength training program, as well as 6 unaffected controls who did not undergo the exercise program. RNA was extracted from these biopsies and RNA-Seq was performed.