Engineered co-cultures of iPSC-derived atrial cardiomyocytes and atrial fibroblasts for modeling atrial fibrillation [I]

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia treatable with antiarrhythmic drugs, but patient responses are highly variable. Human induced pluripotent stem cell-derived atrial cardiomyocytes (iPSC-aCMs) are useful for discovering precision therapeutics, but current platforms yield an immature cellular phenotype and are not easily scalable for high-throughput screening. Here, we report that primary adult atrial, but not ventricular, fibroblasts induced greater functional iPSC-aCM maturation, partly through connexin-40 and ephrin-B1 signaling. We developed a protein patterning process within industry-standard multiwell plates to engineer patterned co-culture (PC) of iPSC-aCMs and atrial fibroblasts that significantly enhanced iPSC-aCM structural, electrical, contractile, and metabolic maturation for 6+ weeks versus conventional mono-/co-cultures. PC displayed greater sensitivity for detecting drug efficacy than monocultures, and enabled the modeling and pharmacological or gene editing treatment of an AF-like electrophysiological phenotype due to a sodium channel mutation. In conclusion, PC is useful to elucidate heterotypic cell signaling in the atria, drug screening, and to model AF. Overall design: Examination of one iPSC-derived atrial cardiomyocyte line with baseline maturation compared to patterned coculture maturation.