GSE183216
Titin truncating variantsin hiPSC-cardiomyocytes inducepathogenic proteinopathy, sarcomeredefect and contractile dysfunction independent of the core contractilemachinery [bulk RNA-seq]
Titintruncating variants(TTNtv) have been identified as the single largestgenetic cause of dilated cardiomyopathy(DCM). In this studywe modeled the disease phenotypes of TTNtv-induced DCM in hiPSC-CMsusing CRISPR/Cas9 genome editing and tissue engineering technologies. Transcriptomic, cellular and micro-tissue studies revealed that TTNtv hiPSC-CMs displayed pathogenic proteinopathy, sarcomere defects, aberrant Na+channel activities and, most importantly, contractile dysfunction. These phenotypes establish a dual mechanism of poison peptide effect and haploinsufficiency that collectively contribute to DCM pathogenesis. On the other hand, TTNtv cellular defects did not interfere with normal function of the core contractile machinery, actin-myosin-troponin-Ca2+complex, and preserved the therapeutic mechanism of sarcomere modulators. Treatment of TTNtv cardiac micro-tissues with investigational sarcomere modulators augmented contractility and resulted in sustained transcriptomicchanges that promotereversalof DCM disease signatures, as revealed by single-cell RNA-seqanalysis.Taken together, our findings depict the underlying pathogenic mechanisms of TTNtv-induced DCMand demonstrate the validity of sarcomere modulators as potentialtherapeutic agentsfor this disease. Overall design: wt and TTNtv/+ hIPSC-cardiomyocytes at 30,90,150 days post differentiation in triplicate.