OXPHOS driven by glycolysis through the malate aspartate shuttle is required for cardiomyocyte re-differentiation and long-term fish heart regeneration [WT_ZF_strain_RNAseq]

In contrast to humans after myocardial infarction, fish can fully regenerate their hearts. However, not all fish are equally able to regenerate, allowing comparative inter- and intra-species analysis to identify novel mechanisms controlling successful heart regeneration. Here, we report a differential regenerative response to cardiac cryo-injury between seven different wild-type zebrafish strains. Correlating this data to single cell and bulk RNAseq data, we identify oxidative phosphorylation (OXPHOS) as a positive regulator of long-term regenerative outcome. OXPHOS levels, driven by Glycolysis through the Malate aspartate shuttle (MAS), increase as soon as cardiomyocyte proliferation decreases, and this increase is required for cardiomyocyte re-differentiation and successful long-term regeneration. We confirm these findings in Astyanax mexicanus and link it to a dynamic temporal sarcomere gene expression programme during cardiomyocyte re-differentiation. These findings challenge the current stance that OXPHOS inhibits regeneration and provide new targetable pathways to enhance heart repair in humans after myocardial infarction. Comparative gene expression profiling analysis of RNA-seq data for 7 different wild-type zebrafish strains (AB, KCL, NA, SAT, TL, TU and WIK). Zebrafish underwent cryo-injury of the cardiac ventricle and hearts were isolated at 1 and 7 days post cryo-injury as well as uninjured control.