Evolving extracellular matrices evoke signaling pathways that govern cardiomyocyte maturation

About This Grant

PROJECT SUMMARY Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) hold promise for cardiac disease modeling, drug testing, medical device testing, and regenerative medicine. However, their limited functional maturity in vitro remains a major barrier to widespread application. We recognize the crucial role of distinct and specific mechanical loads in cardiac morphogenesis and seek to co-opt signals downstream of mechanical engagement to drive maturation of hPSC-CMs. In particular, we seek to establish a causal link between mechanical stimulation and hPSC-CM maturation by focusing on the contribution of extracellular matrix (ECM) proteins, the primary family of proteins that mediate and confer mechanical force to the cell. Our lab has developed a novel human, chambered cardiac muscle pump model (hChaMP) capable of simulating both stretch and shear forces akin to a native cardiac cycle. We have begun to incorporate epicardial-derived cells (namely cardiac fibroblasts, CF) into the hChaMP (termed epi-ChaMP via a previously funded R01), as CFs remodel the ECM in response to mechanical stimulation. We also have expertise in cutting-edge computational modeling approaches to refine mechanical stimulation parameters and in fully characterizing the composition of the ECM following mechanical stimulation. Given our unique ecosystem, we can test the hypothesis that CM maturation is augmented in the epi-hChaMP via potent signaling of an evolving ECM deposited by CF in response to dynamic volumetric pressure. We will do so by developing and validating a computational fluid-structure interaction model that accurately replicates native cardiac pressure profiles in the epi-hChaMP (Aim 1), testing the mechanistic role of ECM deposition and remodeling by FBs in driving cardiomyocyte and tissue-scale maturation under physiologic loading (Aim 2), and by applying a statistical optimization framework to define dynamic volumetric loading regimes that maximize functional maturation of epi-hChaMP tissues. The proposal directly addresses reviewer feedback through clearer model differentiation, enhanced methodological descriptions, and inclusion of a non- cardiac fibroblast control. Completion of this project will reveal unappreciated contributions of ECM to CM maturation (Basic Science Innovation) and will yield a robust in vitro human muscle pump with unprecedented physiological relevance (Applied Science Innovation).