Figure 1.

MSI2 is upregulated in DM1 samples

Quantification by qRT-PCR of the relative expression of (A) miR-7 and (B) MSI2 in human biopsies (gray; n = 17 controls; n = 16 DM1), cultured primary myoblasts (blue; n = 3), and transdifferentiated myoblasts (TDMs; orange; n = 1). miR-7 quantification is relative to endogenous U1 and U6 levels, and MSI2 is referenced to GADPH and GPI expression. Sample sizes indicate biological replicates. At least three independent experiments were carried out for primary myoblasts and TDMs, and three technical replicates were performed from each biological sample in all cases. Representative confocal images of MSI2 immunostained (green; C) healthy controls and (D) DM1 TDMs. Nuclei were counterstained with DAPI (blue). Scale bar, 20 μm. (E) Analysis of relative protein levels of MSI2 by western blot and representative blots of protein extracts obtained from human biopsies, cultured primary myoblasts, and TDMs. β-actin and GAPDH were used as endogenous controls to normalize protein levels of TDMs or human biopsies and primary myoblasts, respectively. Samples sizes as in (A) except n = 3 for primary myoblasts and TDMs. The scatterplots show the median with interquartile range for human biopsies and mean ± SEM for cultured cells. ∗p < 0.05, ∗∗p < 0.01, and ∗∗∗p < 0.001 according to Student’s t test. (F) Pearson’s correlations between the relative miR-7 and MSI2 protein expression levels in human biopsies (gray). (G) The scatterplot represents MSI2 transcripts per million (TPM) in biopsies from 40 DM1 patients and 10 controls (according to Wang et al.²³) with the median and interquartile range. ∗∗∗∗p < 0.0001 according to Student’s t test. (H) Pearson’s correlation between MSI2 TPM in DM1 biopsies and ankle dorsiflexion strength (ADS) measured in biopsy donors according to Wang et al.²³