RESUMO
Endothelial cells are a heterogeneous population with various organ-specific and conserved functions that are critical to organ development, function, and regeneration. Here we report a Sox17-Erg direct reprogramming approach that uses cardiac fibroblasts to create differentiated endothelial cells that demonstrate endothelial-like molecular and physiological functions in vitro and in vivo. Injection of these induced endothelial cells into myocardial infarct sites after injury results in improved vascular perfusion of the scar region. Furthermore, we use genomic analyses to illustrate that Sox17-Erg reprogramming instructs cardiac fibroblasts toward an arterial-like identity. This results in a more efficient direct conversion of fibroblasts into endothelial-like cells when compared to traditional Etv2-based reprogramming. Overall, this Sox17-Erg direct reprogramming strategy offers a robust tool to generate endothelial cells both in vitro and in vivo, and has the potential to be used in repairing injured tissue.
Assuntos
Reprogramação Celular , Células Endoteliais , Fibroblastos , Fatores de Transcrição SOXF , Regulador Transcricional ERG , Animais , Camundongos , Diferenciação Celular , Reprogramação Celular/genética , Células Endoteliais/metabolismo , Células Endoteliais/citologia , Fibroblastos/metabolismo , Fibroblastos/citologia , Proteínas HMGB/metabolismo , Proteínas HMGB/genética , Camundongos Endogâmicos C57BL , Infarto do Miocárdio/patologia , Miocárdio/citologia , Miocárdio/metabolismo , Fatores de Transcrição SOXF/metabolismo , Fatores de Transcrição SOXF/genética , Regulador Transcricional ERG/genética , Regulador Transcricional ERG/metabolismoRESUMO
Direct reprogramming of fibroblasts into induced cardiomyocytes holds great promise for heart regeneration. Although considerable progress has been made in understanding the transcriptional and epigenetic mechanisms of iCM reprogramming, its translational regulation remains largely unexplored. Here, we characterized the translational landscape of iCM reprogramming through integrative ribosome and transcriptomic profiling, and found extensive translatome repatterning during this process. Loss of function screening for translational regulators uncovered Ybx1 as a critical barrier to iCM induction. In a mouse model of myocardial infarction, removing Ybx1 enhanced in vivo reprogramming, resulting in improved heart function and reduced scar size. Mechanistically, Ybx1 depletion de-repressed the translation of its direct targets SRF and Baf60c, both of which mediated the effect of Ybx1 depletion on iCM generation. Furthermore, removal of Ybx1 allowed single factor Tbx5-mediated iCM conversion. In summary, this study revealed a new layer of regulatory mechanism that controls cardiac reprogramming at the translational level.