Optimized protocol for direct cardiac reprogramming in mice using Ascl1 and Mef2c

Direct cardiac reprogramming refers to the conversion of fibroblasts into cardiomyocyte-like cells (iCMs) without going through an intermediate progenitor stage. Here, we present a protocol for direct cardiac reprogramming in mice using Ascl1 and Mef2c. We describe steps for isolating primary neonatal mouse cardiac fibroblast, preparing retrovirus encoding reprogramming factors, and efficient cardiac reprogramming with Ascl1 and Mef2c. The resulting iCMs display cardiomyocyte-like sarcomere structure, gene expression, and calcium flux. For complete details on the use and execution of this protocol, please refer to Wang et al. (2022).1.