Antisense‐mediated exon skipping: a therapeutic strategy for titin‐based dilated cardiomyopathy

Abstract

Frameshift mutations in the TTN gene encoding titin are a major cause for inherited forms of dilated cardiomyopathy (DCM), a heart disease characterized by ventricular dilatation, systolic dysfunction, and progressive heart failure. To date, there are no specific treatment options for DCM patients but heart transplantation. Here, we show the beneficial potential of reframing titin transcripts by antisense oligonucleotide (AON)-mediated exon skipping in human and murine models of DCM carrying a previously identified autosomal-dominant frameshift mutation in titin exon 326. Correction of TTN reading frame in patient-specific cardiomyocytes derived from induced pluripotent stem cells rescued defective myofibril assembly and stability and normalized the sarcomeric protein expression. AON treatment in Ttn knock-in mice improved sarcomere formation and contractile performance in homozygous embryos and prevented the development of the DCM phenotype in heterozygous animals. These results demonstrate that disruption of the titin reading frame due to a truncating DCM mutation can be restored by exon skipping in both patient cardiomyocytes in vitro and mouse heart in vivo, indicating RNA-based strategies as a potential treatment option for DCM.

Subtype-specific promoter-driven action potential imaging for precise disease modelling and drug testing in hiPSC-derived cardiomyocytes

“…Transduction efficiency, as assessed by quantitative polymerase chain reaction (PCR) on genomic DNA, was high for all lentiviral constructs and comparable with that of PGK-VSFP (see Supplementary material online, Results and Figure S1C ). Five days after viral infection of single CMs dissociated from 3-month-old cardiac explants obtained by EB differentiation, 11 VSFP signal from each lentiviral construct was detectable ( Figure 2A –C). MLC2v-VSFP was expressed in >70% of CMs, while SLN-VSFP and SHOX2-VSFP marked around 10 and 5% of the cell population, respectively (Supplementary material online, Figure S2 B ), consistent with the previously reported percentage of ventricular-, atrial-, and nodal-like subtypes in EB-differentiated iPSC-CMs.…”

Thick Filament Protein Network, Functions, and Disease Association

“…However, Gramlich and colleagues recently developed an antisense exon-skipping oligonucleotide approach as a potential therapy for treating truncating titin mutations (190). Importantly, this approach prevented the development of DCM in mice heterozygous for the frameshift mutation Ser14450fsX4, and partially restored sarcomeric organization in patient-derived cardiomyocytes (180, 190). Mechanistically, the exon skipping approach functions via splicing out exon 326 where a 2bp insertion leads to frameshift and the generation of a premature stop codon (180,190).…”

Efficient exon skipping of SGCG mutations mediated by phosphorodiamidate morpholino oligomers

“…Eteplirsen represented an achievement in the fields of neuromuscular disease and molecular gene correction, and it was followed by the approval of nusinersen for treating spinal muscular atrophy (SMA) (23,24). Progress toward clinical development of antisense-mediated splice modulating therapy has expanded beyond the treatment of DMD to include other disorders, such as Pompe disease, cystic fibrosis, cardiomyopathies, and laminopathies (25)(26)(27)(28)(29).…”