Key result
Troponin-T ΔK210 mutation reduces cardiomyocyte force per area ~22% and impairs stiffness adaptation.
Why the study?
It is not well understood how sarcomeric protein mutations in familial dilated cardiomyopathy lead to alterations in cellular organization and contractility.
Does the troponin-T ΔK210 mutation impair contractility and mechanosensing in human induced pluripotent stem cell-derived cardiomyocytes?
Does the troponin-T ΔK210 mutation impair contractility and mechanosensing in human induced pluripotent stem cell-derived cardiomyocytes?
Absolute Event Rate: 0.25% vs 0.32%
p-value: p=0.01
The troponin-T ΔK210 mutation causes dilated cardiomyopathy by broadly impairing cellular mechanosensing, causing hypertrophy, and directly reducing contractility.
May implicate mechanosensing defects in troponin-T DCM pathogenesis; leaves open validation in human models before clinical relevance.
Familial dilated cardiomyopathy (DCM) is a leading cause of sudden cardiac death and a major indicator for heart transplant. The disease is frequently caused by mutations of sarcomeric proteins; however, it is not well understood how these molecular mutations lead to alterations in cellular organization and contractility. To address this critical gap in our knowledge, we studied the molecular and cellular consequences of a DCM mutation in troponin-T, ΔK210. We determined the molecular mechanism of ΔK210 and used computational modeling to predict that the mutation should reduce the force per sarcomere. In mutant cardiomyocytes, we found that ΔK210 not only reduces contractility but also causes cellular hypertrophy and impairs cardiomyocytes' ability to adapt to changes in substrate stiffness (e.g., heart tissue fibrosis that occurs with aging and disease). These results help link the molecular and cellular phenotypes and implicate alterations in mechanosensing as an important factor in the development of DCM.
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Clippinger et al. (2019) studied Familial dilated cardiomyopathy (DCM). Troponin-T ΔK210 mutation vs. Wild-type troponin-T was evaluated on Cellular force per area (µN/µm2) (p=0.01). The troponin-T ΔK210 mutation significantly reduced cellular force per area and impaired the ability of cardiomyocytes to adapt to changes in substrate stiffness compared to wild-type.
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