Tunable Magnetorheological Elastomer Substrates for Studying Mechano-Genetic Interactions in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disease. While sarcomeric genomic variants drive HCM, a role for mechanical stress in disease pathogenesis is increasingly appreciated. However, existing in vitro models of HCM rely on model systems (e.g., hydrogels) with static mechanical properties, precluding investigation of how dynamic mechanical loading interacts with genetic susceptibility during disease initiation. Here, we leveraged a dynamically tunable magnetorheological elastomer (MRE) platform to model progressive mechanical stiffening in order to study mechano-genetic interactions in human induced pluripotent stem cell (hiPSC) derived cardiomyocytes harboring an HCM-associated MYBPC3 frameshift (MYBPC3fs) loss-of-function variant. Dynamic stiffening selectively unmasked pathological structural remodeling in MYBPC3fs cardiomyocytes while producing only modest changes in isogenic controls, suggesting that MYBPC3fs confers heightened mechanosensitivity. In MYBPC3fs cardiomyocytes, mechanical stiffening drove hypertrophic remodeling, sarcomere disorganization, nuclear remodeling, dysregulated NFAT3 signaling, and aberrant cell-cycle activity. MRE stiffening also drove fibroblast-to-myofibroblast transition in primary cardiac fibroblasts, recapitulating early fibrotic remodeling. Together, these findings position dynamically tunable MRE substrates as a human-relevant platform for dissecting mechano-genetic disease mechanisms and evaluating therapies targeting mechanotransduction pathways in HCM.