Figure 2
iPSC-CMs from the DM1 patients show hallmarks of the disease. (A) Fluorescence in situ hybridization (FISH) using a Cy3-CAG probe (red) to detect RNA foci in CTRL, DM1-300, and DM1-1300 cardiomyocytes. The middle panels show a zoom-in of nuclei, and the bottom panels show cTnT co-expression (green). The nuclei are counterstained with DAPI (cyan). iPSC-CMs from the DM1-300 and DM1-1300 patients have high levels of RNA foci in the nuclei. No foci signals were detected in iPSC-CMs from the CTRL. Scale bar: 20 µM. Images were acquired using Zeiss ImagerM2 LSM confocal microscope and processed with ZEN software (Zeiss). (B,C) Bar graphs showing splicing mis-regulations of MBNL1 (B) and MBNL2 (C) in iPSC-CMs from the CTRL (n = 3), DM1-300 (n = 3) and DMI-1300 (n = 3). The results are expressed as a percent splice index (PSI) obtained from ASPCR assays. (D) RT-qPCR quantification of the percentage of SCN5A mRNA, including adult exon 6b, after 30 days of maturation in iPSC-CMs from CTRL and DM1 iPSC-CMs. Bars indicate SEM. Significant differences were observed between CTRL (n = 3) and DM1-300 (n = 3) (δδp < 0.01), between CTRL and DM1-1300 (n = 3) (*p < 0.05, ***p < 0.001), and between DM1-300 and DM1-1300 (#p < 0.05) as determined by ANOVA and Tukey’s post hoc test. A replicate (n) represents an RNA extract from a single independent differentiation.
