Transcriptional Remodeling in Human Cardiac Fibroblasts and Myocytes Induced by Oxygen-Dependent Crosstalk

Myocardial infarctions are caused by coronary occlusions that deprive downstream myocardial tissue of oxygenated blood, leading to localized necrosis of cardiac myocytes. Hypoxic injury drives a remodeling process in which cardiac fibroblasts activate and synthesize matrix proteins to form a scar. During this process, cardiac cells are exposed to an oxygen gradient at the infarct border zone that transitions from 0% oxygen at the site of injury to 10% oxygen in healthy myocardium. However, the impact of any crosstalk between hypoxic cardiac fibroblasts and neighboring, normoxic (10% oxygen) cardiac cells is unexplored because conventional research tools cannot re-create spatially heterogeneous oxygen landscapes. Here, we used a microfluidic device to co-culture hypoxic cardiac fibroblasts with (1) normoxic cardiac fibroblasts or (2) normoxic human induced pluripotent stem cell (hiPSC)-derived cardiac myocytes. We then compared their transcriptome to the same cells cultured in uniform hypoxia or normoxia. These data contribute to more advanced understanding of how oxygen-dependent crosstalk between cardiac cells impacts the wound healing process post-myocardial infarction. Overall design: Primary human adult cardiac fibroblasts or human induced pluripotent stem cell (hiPSC)-derived cardiac myocytes were cultured on fibronectin-coated PDMS microfluidic devices designed to expose cells to 0% oxygen, 10% oxygen, or adjacent co-culture regions of 0% and 10% oxygen. After 24h of oxygen modulation, cells from each half of the co-culture region were immediately separated with a razor blade and all conditions (0% control, 0% in co-culture, 10% in co-culture, and 10% control) were lysed. RNA was isolated and sequenced, and gene expression was analyzed using Partek Flow Genomics Software.