Abstract 13073: Antisense Transcripts Regulate Titin Alternative Splicing and Sarcomere Function in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes

• Published in: Circulation (New York, N.Y.) N.Y.), 2022-11, Vol.146 (Suppl_1), p.A13073-A13073
• Main Authors: Celik, Selvi, Hyrefelt, Ludvig, Czuba, Tomasz, Andre, Oscar, Lindquist, Lovisa, Grossi, Mario, Nordenfelt, Pontus, Smith, Gustav, Gidlof, Olof
• Format: Article
• Language: English
• ISSN: 0009-7322; 1524-4539
• DOI: 10.1161/circ.146.suppl_1.13073

The giant protein Titin is an essential structural component of the sarcomere and a key determinant of passive tension during diastole. Titin tension is regulated by alternative splicing within the spring-like domains in the I-band region of TTN pre-mRNA. The cardiac RNA-binding protein RBM20 has been shown to promote TTN exon skipping during splicing, but additional factors are likely involved. We hypothesized that a natural antisense transcript in the TTN locus (TTN-AS1) could regulate TTN splicing in cis through recruitment of spliceosome components. Through single nuclei RNA-Seq and RNA fluorescence in situ hybridization (ISH) on human cardiac tissue and iPS-derived cardiomyocytes (iPS-CM), we showed that the expression of TTN-AS1 was restricted to cardiomyocyte nuclei. The percent spliced in (PSI) of each TTN exon was calculated based on RNA-Seq data from iPS-CM (n=3) and 26 exons (all in the I-band region) that are normally spliced out were included to a significantly higher extent (adjusted p