(P016) USING GENETICALLY-ENCODED BIOSENSORS TO PROFILE MOLECULAR SIGNALLING IN INDUCED PLURIPOTENT STEM CELL-CARDIOMYOCYTES DERIVED FROM PATIENTS WITH DILATED CARDIOMYOPATHY

Background: Dilated or non-ischemic cardiomyopathy (DCM) develops when the left ventricle of the heart enlarges, compromising its function and diminishing its capacity to pump blood to the body’s organs. Disease progression can lead to end-stage heart failure and the need for cardiac transplantation. DCM is a complex cardiovascular disease in which underlying causes can be genetic, environmental or idiopathic. Despite this, all forms of heart failure with reduced ejection fraction are treated with the same guideline directed medical therapy and interventions as per current standard of practice. Incomplete molecular knowledge of disease pathology poses challenges for drug discovery efforts as effective therapeutic strategies remain elusive. Decades of research using primary cells or animal models have increased understanding of DCM, but this has been hampered due to the inaccessibility of human cardiomyocytes to model cardiac disease, in vitro, in a dish.

METHODS AND RESULTS: Our goal is to leverage cardiomyocytes derived from human induced pluripotent stem cell (hiPSC) expressing genetically-encoded biosensors to define alterations in molecular signalling from individual patients with DCM. We obtained blood samples from patients with a diagnosis of DCM over age 18 years. Standard operating protocols were developed to reliably culture hiPSC lines from patient blood samples, which were validated by multiple techniques (immunofluorescence, trilineage differentiation, karyotyping). Cardiomyocytes were differentiated from patient-derived hiPSCs. Clinical data was collected by chart review. The patient population was 71% male and 29% female (N=201). Median age was 57 years. 50% of patients had idiopathic DCM (no established etiology). Using the biosensor RGECO-Tnt, pilot data demonstrates patient-specific effects on calcium handling. FRET-based biosensors of PKA or ERK activation show differences not only between DCM patients and normal controls, but also between males and females with DCM.

Conclusion: By characterizing the pathophysiology of DCM in a patient-specific manner using high content biosensor-based assays with a translational ‘Heart-in-a-Dish’ model, we aim to uncover individualized molecular mechanisms of DCM as a pathway to development of personalized medicine.