Downregulation of Scd1 promotes cardiac reprogramming by enhancing mitochondrial metabolism through PGC1α [RNA-seq]

Direct cardiac reprogramming of fibroblasts into induced cardiac-like myocytes (iCMs) has emerged as a promising therapeutic strategy to remuscularize injured myocardium. However, the intrinsic metabolic demands that drive the iCM program and maturity remain unclear. Here, we induce efficient iCM production and maturation through metabolic pathway modulations. To explore the metabolic heterogeneity of iCMs, we performed single cell RNA sequencing (scRNA-seq) at reprograming day 14. Using single-cell metabolic flux estimation and flux balance analysis on day 14 iCM, we characterized the metabolic heterogeneity of iCMs and identified fatty acid oxidation (FAO) as a critical factor in iCM conversion. Mechanistically, we proved that Scd1 knockdown activates PGC1α/PPARβ transcription signal, which further promotes cardiac reprogramming, and induced cardiomyocytes demonstrated more frequent beating, calcium oscillation, and higher energy metabolism as evidenced by increased mitochondrial respiration and gene expression associated with FAO, which provides a new strategy and theoretical basis for cardiac regeneration and repair. Our findings collectively highlight FAO as a key determinant of iCM fate and offer new therapeutic avenues for advancing reprogramming strategies.