Harnessing molecular mechanism for precision medicine in dilated cardiomyopathy caused by a mutation in troponin T

Abstract

Familial dilated cardiomyopathy (DCM) is frequently caused by autosomal dominant point mutations in genes involved in diverse cellular processes, including sarcomeric contraction. While patient studies have defined the genetic landscape of DCM, genetics are not currently used in patient care, and patients receive similar treatments regardless of the underlying mutation. It has been suggested that a precision medicine approach based on the molecular mechanism of the underlying mutation could improve outcomes; however, realizing this approach has been challenging due to difficulties linking genotype and phenotype and then leveraging this information to identify therapeutic approaches. Here, we used multiscale experimental and computational approaches to test whether knowledge of molecular mechanism could be harnessed to connect genotype, phenotype, and drug response for a DCM mutation in troponin T, deletion of K210. Previously, we showed that at the molecular scale, the mutation reduces thin filament activation. Here, we used computational modeling of this molecular defect to predict that the mutant will reduce cellular and tissue contractility, and we validated this prediction in human cardiomyocytes and engineered heart tissues. We then used our knowledge of molecular mechanism to computationally model the effects of a small molecule that can activate the thin filament. We demonstrate experimentally that the modeling correctly predicts that the small molecule can partially rescue systolic dysfunction at the expense of diastolic function. Taken together, our results demonstrate how molecular mechanism can be harnessed to connect genotype and phenotype and inspire strategies to optimize mechanism-based therapeutics for DCM. Significance statementDilated cardiomyopathy (DCM), a leading cause of heart failure, is characterized by the inability of the heart to perfuse the body at normal filling pressures. There are multiple causes of DCM, including point mutations in sarcomeric proteins, but most patients receive similar courses of treatment, regardless of the underlying cause of the DCM. Many patients remain unserved by current therapies, and there is a need for new approaches. Here, we use multiscale experimental and computational approaches to demonstrate how knowledge of molecular mechanism can be harnessed to accurately predict the effects of a patient-specific mutation and responses to presumptive therapeutics. Our approach lays the foundation for a precision medicine approach to DCM.